[Federal Register Volume 62, Number 71 (Monday, April 14, 1997)]
[Proposed Rules]
[Pages 18170-18200]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-9056]



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Part II





Department of Transportation





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Federal Highway Administration



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49 CFR Parts 390, 392, and 393



Parts and Accessories Necessary for Safe Operation; General Amendments; 
Proposed Rule

  Federal Register / Vol. 62, No. 71 / Monday, April 14, 1997 / 
Proposed Rules  

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DEPARTMENT OF TRANSPORTATION

Federal Highway Administration

49 CFR Parts 390, 392, and 393

[FHWA Docket No. MC-97-5]
RIN 2125-AD40


Parts and Accessories Necessary for Safe Operation; General 
Amendments

AGENCY: Federal Highway Administration (FHWA), DOT.

ACTION: Notice of proposed rulemaking (NPRM); request for comments.

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SUMMARY: The FHWA is proposing to amend part 393 of the Federal Motor 
Carrier Safety Regulations (FMCSRs), Parts and Accessories Necessary 
for Safe Operation. The amendments are intended to remove obsolete and 
redundant regulations; respond to several petitions for rulemaking; 
provide improved definitions of vehicle types, systems, and components; 
resolve inconsistencies between part 393 and the National Highway 
Traffic Safety Administration's Federal Motor Vehicle Safety Standards 
(49 CFR 571); and codify certain FHWA regulatory guidance concerning 
the requirements of part 393. Generally, the amendments do not involve 
the establishment of new or more stringent requirements but a 
clarification of existing requirements. This action is consistent with 
the President's Regulatory Reinvention Initiative and furthers the 
FHWA's ongoing Zero-Base Regulatory Review in that it proposes to make 
many sections more concise, easier to understand and more performance 
oriented.

DATES: Written comments must be received on or before June 13, 1997.

ADDRESSES: Signed, written comments should refer to the docket number 
that appears at the top of this document and must be submitted to the 
Docket Clerk, U.S. DOT Dockets, Room PL-401, 400 Seventh Street, SW., 
Washington, DC 20590-0001. All comments received will be available for 
examination at the above address between 10 a.m. and 5 p.m., e.t., 
Monday through Friday, except Federal holidays. Those desiring 
notification of receipt of comments must include a self-addressed, 
stamped envelope or postcard.

FOR FURTHER INFORMATION CONTACT: Mr. Larry W. Minor, Office of Motor 
Carrier Research and Standards, HCS-10, (202) 366-4009; or Mr. Charles 
E. Medalen, Office of the Chief Counsel, HCC-20, (202) 366-1354, 
Federal Highway Administration, 400 Seventh Street, SW., Washington, DC 
20590. Office hours are from 7:45 a.m. to 4:15 p.m., e.t., Monday 
through Friday, except Federal holidays.

SUPPLEMENTARY INFORMATION:

Background

    On December 7, 1988, the FHWA published a final rule on parts and 
accessories necessary for safe operation (53 FR 49380). The final rule 
included amendments to the requirements for lamps and reflective 
devices, brake systems, fuel systems, frames and frame assemblies, 
suspension systems, steering systems, and axle assemblies. This action 
was taken to implement sections 206 and 210 of the Motor Carrier Safety 
Act of 1984 (the Act) (49 U.S.C. 31136 and 31142) and to ensure that 
commercial motor vehicles are equipped with all parts and accessories 
considered necessary for safe operation. Since the publication of the 
final rule, the FHWA has received numerous petitions for rulemaking and 
requests for interpretation of the requirements of part 393 which have 
raised the need for additional amendments to clarify several provisions 
of the 1988 final rule. In addition, the National Highway Traffic 
Safety Administration (NHTSA), the Federal agency responsible for 
establishing safety standards for the manufacture of motor vehicles and 
certain motor vehicle equipment, has made several amendments to its 
Federal Motor Vehicle Safety Standards (FMVSSs) that necessitate 
amendments to the FMCSRs in order to eliminate inconsistencies between 
part 393 and the FMVSSs.

Proposed Amendments

Section-by-Section Discussion of the Proposed Amendments

Section 390.5--Definition of Driveaway-Towaway Operation
    Parts 393 and 396 of the FMCSRs include several exceptions for 
driveaway-towaway operations. A driveaway-towaway operation is defined 
as one in which a motor vehicle constitutes the commodity being 
transported and one or more set of wheels of the vehicle being 
transported are on the surface of the roadway during transportation. 
The driveaway-towaway exceptions are intended to address situations in 
which compliance with some of the vehicle regulations is not 
practicable because of the circumstances surrounding the delivery or 
transportation of the vehicle. Examples of driveaway-towaway operations 
include the delivery of a newly manufactured commercial motor vehicle 
from a manufacturer to a dealership, the delivery of a new or used 
motor vehicle from the dealership to the purchaser, or certain 
movements of vehicles to a repair or maintenance facility. Among the 
provisions of parts 393 and 396 which do not apply to driveaway-towaway 
operations are the requirements for lamps and reflectors, brakes, 
driver vehicle inspection reports, maintenance records, and periodic 
inspection.
    The concept of providing exceptions for such operations dates back 
to the Interstate Commerce Commission's (ICC) May 27, 1939, order under 
Ex-Parte No. MC-2 (14 M.C.C. 669, at 679). A driveaway-towaway 
operation was originally defined by the ICC as ``any operation in which 
a single motor vehicle or combination of motor vehicles, new or used, 
constitutes the commodity being transported and in which the motive 
power of any such motor vehicles is utilized.'' In 1952, the ICC 
revised the definition to read ``any operation in which any motor 
vehicle or motor vehicles, new or used, constitute the commodity being 
transported, when one or more set of wheels of any such motor vehicle 
or motor vehicles are on the roadway during the course of 
transportation; whether or not any such motor vehicle furnishes the 
motive power.'' (17 FR 4422, 4423, May 15, 1952).
    The current definition of a driveaway-towaway operation was 
published on May 19, 1988 (53 FR 18052). It has become apparent that 
this definition does not provide sufficient guidance in identifying the 
specific types of vehicle operations covered. The FHWA has received 
numerous requests for clarification of the applicability of the 
driveaway-towaway exceptions to construction equipment and storage 
trailers. Typically storage trailers are parked for several weeks to 
several months at a construction site and moved occasionally from one 
site to another. Construction equipment is also moved only occasionally 
from site to site. Therefore, the FHWA is proposing to limit the 
definition of a driveaway-towaway operation to motor vehicles being 
transported (1) between a vehicle manufacturer and a dealership or a 
purchaser, (2) between a dealership, or other entity selling or leasing 
the vehicle, and a purchaser or lessee, (3) to a maintenance/repair 
facility for the repair of disabling damage (as defined in Sec. 390.5), 
or (4) by means of a saddle-mount. In addition, the driveaway-towaway 
exception would only apply to those cases in which the motor vehicles 
are not transporting cargo or passengers. The proposed revision is 
intended to reduce confusion.

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Section 392.33--Obscured Lamps or Reflectors
    The FHWA is proposing to amend Sec. 392.33 to include an exception 
for the obstruction of trailer conspicuity treatments on the front end 
protection device. The NHTSA requires trailer manufacturers to apply 
retroreflective sheeting to the front end protection devices or 
headerboards of trailers manufactured on or after December 1, 1993 (49 
CFR 571.108, S5.7.1.4). Since the headerboard is located at the front 
of flatbed trailers, the cargo may, depending upon its height, obstruct 
the conspicuity material located on the headerboard. The FHWA 
recognizes that this temporary obstruction of the reflective material 
cannot be avoided in many cases and does not believe that it would be 
appropriate to penalize motor carriers.
Section 393.1--Scope of the Rules of This Part
    The FHWA is proposing a revision of Sec. 393.1 to clarify the 
applicability of the requirements of part 393. Although Sec. 390.3 
explains the applicability of the FMCSRs, and Sec. 390.5 defines the 
term ``commercial motor vehicle,'' many private motor carriers of 
property and private motor carriers of passengers do not understand the 
applicability of the provisions in part 393 when a lightweight vehicle 
is used to tow a trailer in interstate commerce. Vehicles with a GVWR 
below 4,536 kg (10,001 pounds) or designed to transport less than 16 
passengers are not subject to the FMCSRs when operated singly in 
interstate commerce unless placardable quantities of hazardous 
materials are being transported. However, when a small vehicle is 
coupled to a trailer, the gross combination weight rating (GCWR) often 
exceeds 4,536 kg (10,001 pounds), making the combination subject to the 
FMCSRs.
    Part 393 cross-references several Federal Motor Vehicle Safety 
Standards (FMVSSs) which distinguish between vehicles above and below 
4,536 kg (10,001 pounds) and passenger vehicles designed to transport 
fewer than 16 passengers. This rulemaking includes numerous proposals 
to clarify the cross-references to the FMVSS so that carriers and 
inspectors can readily locate the applicable paragraphs within the 
FMVSSs. The amendment to Sec. 393.1 is consistent with that goal.
Section 393.5--Definitions
    The FHWA is proposing to amend Sec. 393.5 by adding definitions of 
air brake system, air-over-hydraulic brake subsystem, auxiliary driving 
lamp, boat trailer, brake power assist unit, brake power unit, electric 
brake system, emergency brake, front fog lamp, hydraulic brake system, 
intermodal shipping (cargo) containers, multi-piece windshield, split 
service brake system, tow bar, trailer kingpin, vacuum brake system, 
and windshield. In addition, the definitions for chassis, clearance 
lamp, container chassis, heater, heavy hauler trailer, parking brake 
system, side marker lamps (intermediate), and side marker lamps would 
be revised. The definition of bus would be removed from Sec. 393.5 in 
favor of the definition found in Sec. 390.5.
    The proposed definitions of brake systems and components would make 
the brake requirements under subpart C of part 393 easier to understand 
and enforce.
    The proposed definitions of an air brake system and an air-over-
hydraulic brake subsystem are based upon NHTSA's July 18, 1995, final 
rule on FMVSS No. 121 (60 FR 36741). The NHTSA amended FMVSS No. 121 to 
include a definition of an air-over-hydraulic brake subsystem and to 
make it clear that vehicles equipped with such systems are classified 
as air braked vehicles. In initially issuing FMVSS No. 121, the NHTSA 
stated that ``it should be noted that the term `air brake system' as 
defined in the standard applies to the brake configuration commonly 
referred to as `air-over-hydraulic,' in which failure of either medium 
can result in complete loss of braking ability.'' (36 FR 3817, February 
27, 1971.) Since the NHTSA has considered air-over-hydraulic brake 
systems subject to FMVSS No. 121 for more than 20 years, the FHWA's 
adoption of the NHTSA's definitions should not affect the applicability 
of the brake requirements under part 393.
    The proposed definition of a boat trailer is the same as that 
contained under 49 CFR 571.3. The NHTSA defines boat trailer as ``a 
trailer designed with cradle-type mountings to transport a boat and 
configured to permit launching of the boat from the rear of the 
trailer.'' The FHWA proposes to include this definition because 
Sec. 393.11 contains requirements for lamps and reflectors on boat 
trailers.
    The FHWA is proposing to replace its definition of ``emergency 
brake system'' with the NHTSA's definition for ``emergency brake.'' 
This change will ensure consistency between the FHWA's brake 
regulations covering motor carriers and the NHTSA's regulations 
covering manufacturers.
    The agency is proposing that NHTSA's FMVSS No. 105 definition of a 
split service brake system be included under Sec. 393.5. The inclusion 
of this definition would help to improve the clarity of the hydraulic 
brake system requirements under subpart C of part 393.
    Definitions of an electric brake system and a vacuum brake system 
would be added to Sec. 393.5 to support other proposed revisions to the 
brake system requirements of part 393. Since there are no FMVSSs which 
cover electric and vacuum brake systems, many of the brake requirements 
under part 393 are de facto manufacturing standards. To better identify 
the applicable requirements, several of the proposed revisions to 
subpart C would specifically reference electric and vacuum brakes. The 
proposed definitions would prevent confusion or misunderstandings on 
the part of motor carriers and enforcement officials.
    With regard to the definition of a chassis, the agency is proposing 
to delete the current reference to a ``truck or trailer'' in favor of 
the term ``commercial motor vehicle,'' which includes trucks, truck 
tractors, trailers, buses and converter dollies. This is especially 
necessary since the definition of a truck in Sec. 390.5 explicitly 
excludes truck tractors.
    It is proposed that the definition of a clearance lamp be replaced 
with the Society of Automotive Engineers' (SAE) definition (Glossary of 
Automotive Terms, SP-750, February 1988). The SAE definition provides a 
better description of the location and function of the clearance lamps 
than the current definition in Sec. 393.5.
    As for the definition of a heater, the FHWA proposes to replace the 
reference to paragraph (1) of Sec. 177.834 with a reference to 
paragraph (l). The reference to paragraph (1) was a typographical 
error.
    A definition of a trailer kingpin is being added to cover non-
driveaway-towaway operations. Currently, the definition of a saddle-
mount includes a description of a ``king-pin.'' However, this 
definition does not appear to be appropriate for the trailer kingpin 
nor is the definition the same as that in the SAE's Truck & Bus 
Industry Glossary, SP-732, February 1988. The FHWA would adopt the 
SAE's definition to ensure that definitions in part 393 are consistent 
with industry definitions.
    To clarify the applicability of parking brake requirements, the 
agency is proposing that the definition of a parking brake system in 
Sec. 393.5 be revised to replace the term ``vehicle'' with ``motor 
vehicle,'' which is defined in Sec. 390.5.
    The agency proposes that the definitions of ``side marker lamp

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(intermediate)'' and ``side marker lamp'' be revised to include motor 
vehicles other than trailers. Currently, both terms are defined only in 
the context of trailers. However, side marker lamps are required on 
almost all motor vehicles and intermediate side marker lamps are 
required on almost all motor vehicles more than 914.4 centimeters (cm) 
(30 feet) in length. Therefore the FHWA is proposing to revise the 
definitions to include trucks, truck-tractors, and buses and to make 
both definitions consistent with the requirements under Sec. 393.11 
relating to side marker lamps and FMVSS No. 108, NHTSA's requirements 
for lamps and reflective devices.
    On November 23, 1990, the NHTSA amended its definition of a heavy 
hauler trailer to specifically exclude container chassis trailers (55 
FR 48850). To maintain consistency between the definitions used by the 
FHWA and the NHTSA, the FHWA is proposing to amend its definition of a 
heavy hauler trailer to exclude container chassis trailers.
    The FHWA is proposing to add a definition of intermodal shipping 
container to the FMCSRs to clarify the use of the term in 
Sec. 393.100(e). The definition would be the same as the definition of 
``container'' under Sec. 390.52.

Subpart B--Lighting Devices, Reflectors, and Electrical Equipment

    The FHWA is proposing to revise the title of subpart B to read 
``Lamps, Reflective Devices, and Electrical Wiring.'' The new title 
would be more consistent with the title of FMVSS No. 108, entitled 
``Lamps, reflective devices, and associated equipment.'' The new title 
would reference electrical wiring instead of associated equipment 
because subpart B includes requirements for the electrical wiring for 
several vehicle systems in addition to the lamps required by FMVSS No. 
108.
Section 393.9--Lamps Operable
    The agency is proposing to amend Sec. 393.9 to codify regulatory 
guidance concerning the use of lamps which are not required by 
Sec. 393.11 and FMVSS No. 108, and to address obstruction of lamps.
    Section 393.9 requires that lamps be capable of being operated at 
all times. The FHWA has issued regulatory guidance indicating that 
Sec. 393.9 is only applicable to those lamps which are required by the 
FMCSRs. Therefore, if a motor carrier installs additional lamps which 
are found to be inoperable, for whatever reason, the carrier should not 
be considered in violation of Sec. 393.9. The FHWA proposes to codify 
this regulatory guidance.
Section 393.11--Lighting Devices and Reflectors
    The FHWA is proposing that the title of Sec. 393.11 be revised to 
read ``Lamps and reflective devices'' to maintain consistency between 
the proposed title for subpart B and Sec. 393.11. The FHWA is also 
proposing that motor vehicles manufactured on or after December 25, 
1968, be required to meet the requirements of FMVSS No. 108 in effect 
at the time of manufacture or a later, higher, standard. Currently, 
Sec. 393.11 only requires that vehicles manufactured on or after March 
7, 1989, meet the requirements of FMVSS No. 108. Vehicles manufactured 
prior to March 7 may meet either FMVSS No. 108 or the requirements of 
part 393 in effect on the date of manufacture.
    The NHTSA's FMVSS No. 108 became effective on December 25, 1968, so 
manufacturers have been required to meet these requirements since that 
date. The FHWA's reference to March 7, 1989, under Sec. 393.11 is 
therefore inappropriate. Since vehicles manufactured between December 
25, 1968, and March 7, 1989, were originally manufactured to meet FMVSS 
No. 108, motor carriers who have maintained lamps and reflectors in the 
required locations for these older vehicles would not be affected by 
the proposed revision.
    In addition, the FHWA is proposing to revise Sec. 393.11 to provide 
better guidance on the requirements for trailers, and to correct 
several omissions in Table 1 of that section. The paragraph preceding 
Table 1 does not present a clear statement of the requirements for 
lamps and reflectors.
    On December 10, 1992, the NHTSA published a final rule requiring 
that trailers manufactured on or after December 1, 1993, which have an 
overall width of 2,032 mm (80 inches) or more and a gross vehicle 
weight rating (GVWR) of more than 4,536 kg (10,000 pounds), be equipped 
on the sides and rear with a means for making them more visible on the 
road (57 FR 238). Trailers manufactured exclusively for use as offices 
or dwellings are exempt.
    The NHTSA rule allows trailer manufacturers to install either red 
and white retroreflective sheeting or reflex reflectors. Manufacturers 
of retroreflective sheeting or reflectors are required to certify 
compliance of their product with FMVSS No. 108 (49 CFR 571.108) whether 
the product is for use as original or replacement equipment.
    Currently, Sec. 393.11 requires that all lamps and reflective 
devices on motor vehicles placed in operation after March 7, 1989, meet 
the requirements of FMVSS No. 108 in effect on the date of manufacture. 
Therefore, trailers manufactured on or after December 1, 1993, must 
have reflective devices of the type and in the locations specified by 
FMVSS No. 108. To make certain that all motor carriers operating 
trailers subject to the FMCSRs are aware of their responsibility to 
maintain the conspicuity treatment, the FHWA is proposing the addition 
of detailed language under Sec. 393.11. The FHWA would cross-reference 
the specific paragraphs of FMVSS No. 108 related to the applicability 
of NHTSA's trailer conspicuity standards, the required locations for 
the conspicuity material, and the certification and marking 
requirements.
    The FHWA notes that during the NHTSA rulemaking, the issue of 
requiring conspicuity material on the rear underride device generated 
industry concerns about the maintainability of the retroreflective 
sheeting in that location. As stated in the preamble to NHTSA's 
December 10, 1992, final rule:

    Objections were based on the potential for frequent damage that 
would cause trailers in use to fail inspections by the FHWA. NHTSA 
has observed that the horizontal bar of the underride device is less 
subject to docking impacts than the vertical bars because it is 
below most dock surfaces (and under a NHTSA proposal [a reference to 
the NHTSA's supplemental notice of proposed rulemaking concerning 
rear impact guards (57 FR 252, January 3, 1992)] would be even 
lower). Therefore, the final rule requires retroreflective material 
to be applied to the horizontal device, instead of the vertical ones 
as proposed. NHTSA believes that the original conspicuity material 
should have a long useful life on a large number of trailers, 
especially if it is applied to a recessed surface. However, NHTSA 
recognizes that routine damage, as a practical matter, may be 
unavoidable for some trailers as a consequence of their particular 
use. Therefore, the FHWA will consider the exclusion of conspicuity 
treatment from the rear underride device in any future rulemaking 
concerning trailer conspicuity requirements for vehicles subject to 
49 CFR 393 Parts and Accessories Necessary for Safe Operation, and 
49 CFR 396 Inspection [,Repair,] and Maintenance.

    The proposed cross-reference to the NHTSA conspicuity requirements 
includes a reference to the specific paragraphs within FMVSS No. 108 
concerning the locations for the conspicuity treatments. The proposal 
does not, however, include an exemption to the requirement that motor 
carriers maintain the conspicuity

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material on the rear underride device. The agency requests comments 
from motor carriers on the durability of the conspicuity material 
located on the horizontal member of the rear underride protection 
devices. Commenters are asked to identify the specific types of 
trailers and operating conditions that they believe are associated with 
the durability problems cited in addition to providing color 
photographs of the damaged conspicuity materials.
    The FHWA published an advance notice of proposed rulemaking 
concerning the possibility of retrofitting trailers manufactured prior 
to December 1, 1993, with the red and white reflective material (59 FR 
2811, January 19, 1994). On August 6, 1996, the FHWA announced that it 
would issue a notice of proposed rulemaking to require motor carriers 
to retrofit their trailers with conspicuity material (61 FR 40781). 
Since the issue of retrofitting is being addressed under FHWA Docket 
No. MC-94-1, comments on that subject will not be considered in this 
rulemaking.
    In addition to providing explicit guidance on trailer conspicuity, 
the FHWA proposes to amend Sec. 393.11 to codify certain regulatory 
guidance on the use of amber stop lamps, amber tail lamps, and optical 
combinations which would involve the use of amber tail lamps or amber 
stop lamps. Motor vehicles are required to be equipped with at least 
two red stop lamps and two red tail lamps. However, some motor carriers 
have expressed an interest in using additional stop lamps and/or tail 
lamps that are amber in color.
    Federal Motor Vehicle Safety Standard No. 108 does not allow amber 
as an alternate color for a tail lamp. In an August 23, 1990, 
interpretation to a manufacturer of lamps and reflectors, NHTSA stated 
that ``We have no intention of allowing amber as an alternate color for 
a tail lamp.'' In a December 10, 1991, interpretation to the FHWA, the 
NHTSA indicated that a combination amber turn signal and tail lamp is 
implicitly prohibited by FMVSS No. 108.

    When combined with an amber turn signal lamp, the intensity of 
an amber tail lamp might mask the turn signal operation. Because 
motorists are not used to seeing steady burning amber lamps on the 
rear of vehicles, amber taillamps could lead to momentary confusion 
of a driver following the trailer when the stop lamps are activated, 
thereby impairing the effectiveness of the stop signal. The presence 
of simultaneously burning amber and red taillamps could also create 
some confusion of a following driver approaching the trailer from 
around a corner to its rear. Thus we have concluded that a 
combination amber turn signal and taillamp is implicitly prohibited 
by Standard No. 108.

    The FHWA agrees that motorists are not used to seeing amber lamps 
used in conjunction with red lamps to signal that the vehicle is 
stopping and believes the FMCSRs should be amended explicitly to 
prohibit the use of amber tail lamps.
    To ensure that the proposed prohibition does not conflict with 
FMVSS No. 108, the FHWA reviewed the NHTSA requirements. Section S5.1.3 
of FMVSS No. 108 prohibits the installation of supplementary lighting 
equipment that ``impairs the effectiveness of lighting equipment 
required by this standard.'' Although the determination of impairment 
is initially that of the vehicle's manufacturer in certifying that the 
vehicle meets all applicable FMVSSs, the NHTSA may review that 
determination and, if clearly erroneous, inform the manufacturer of its 
views.
    Since Sec. 393.11 cross-references FMVSS No. 108, the FHWA's 
regulatory guidance on the use of amber stop lamps and tail lamps is 
generally contingent upon a NHTSA determination as to whether or not 
the lamp impairs the effectiveness of other rear lamps. While 
certification by the vehicle manufacturer and subsequent review by the 
NHTSA address the vehicle manufacturer's role in the safe operation of 
the CMV, a less complicated approach is needed to ensure that the 
FMCSRs are easy to understand, use, and enforce.
    Explicit guidance is needed to ensure that once a vehicle 
manufacturer certifies that a vehicle meets all applicable FMVSSs, the 
motor carrier does not modify it in a manner inconsistent with FMVSS 
No. 108. The FHWA is not aware of any vehicle manufacturers that use 
amber stop lamps or tail lamps as standard equipment. Consequently, the 
proposed restriction would (1) discourage motor carriers from asking 
vehicle manufacturers to install amber tail lamps and/or stop lamps on 
vehicles as optional equipment and (2) prohibit the motor carrier from 
installing or using such devices on its commercial motor vehicles.
    With regard to omissions in Table 1 in Sec. 393.11, the FHWA is 
proposing amendments to footnotes 4 through 10 to address 
inconsistencies with other sections of subpart B to part 393. In 
addition, the agency is proposing to correct the listing for clearance 
lamps and reflex reflectors and to include metric units in describing 
the location of the required lamps and reflectors.
    The current listing for clearance lamps omits reference to footnote 
8 concerning pole trailers and does not include reference to the 
provision in FMVSS No. 108 (S5.1.1.9) for clearance lamps on boat 
trailers. Under FMVSS No. 108, a boat trailer with an overall width of 
2,032 mm (80 inches) or more is not required to be equipped with both 
front and rear clearance lamps provided an amber (to the front) and red 
(to the rear) clearance lamp is located at or near the midpoint on each 
side to indicate the extreme width of the trailer. This provision for 
clearance lamps on boat trailers would be covered under a new footnote 
17.
    The listings for reflex reflectors (front side) and side marker 
lamps (front) are being revised to address an inconsistency between 
Sec. 393.11 and FMVSS No. 108 (S5.1.1.15). Under FMVSS No. 108 a 
trailer that is less than 1,829 mm (6 feet) in length (including the 
trailer tongue) need not be equipped with front side marker lamps and 
front side reflex reflectors. This exception would be covered under a 
new footnote 16.
    The FHWA is proposing to remove the last sentence in footnote 4, 
which requires that the rear side marker lamps be visible in the 
rearview mirror. This requirement is impractical and is inconsistent 
with FMVSS No. 108. Section 571.108 (S5.1.1.8) incorporates by 
reference the Society of Automotive Engineers (SAE) recommended 
practice Clearance, Side Marker, and Identification Lamps, (SAE J592e, 
July 1972) which provides photometric standards. These standards cover 
geometric visibility angles of 45 degrees left to 45 degrees right and 
10 degrees up to 10 degrees down. In order for the rear side marker 
lamps to be visible in the rearview mirrors the left to right angles 
would each have to be approximately 85 degrees. Since side marker lamps 
which meet the minimum standards contained in SAE J592e generally are 
not visible in the rearview mirror, the agency is proposing to amend 
footnote 4.
    The FHWA is proposing editorial changes to footnotes 5 through 8 to 
improve the manner in which the requirements are presented. For 
instance, in footnote 5 the change would make it clear that converter 
dollies are only required to have one stop lamp and one tail lamp. The 
current wording, when combined with the legend at the end of 
Sec. 393.11, could be construed as requiring two stop lamps and two 
tail lamps.
    Amendments to footnotes 9 and 10 would remove the requirements that 
projecting loads be equipped with

[[Page 18174]]

lamps and reflectors during daylight hours. There is no apparent safety 
benefit for requiring lamps and reflectors on projecting loads during 
times when lamps are not required to be used.
    Footnote 15 would be revised to incorporate language consistent 
with certain FMVSS No. 108 options--covered under S5.3.1.1.1, S5.3.1.4, 
S5.3.1.6--on the locations for clearance lamps.
Section 393.17--Lamps and Reflectors, Driveaway-Towaway Operations
    The FHWA proposes to change the wording of the diagrams which 
illustrate the requirements of Sec. 393.17. The diagrams incorrectly 
reference Secs. 393.25(e) and 393.26(d) and would be amended to 
reference Sec. 393.11, which covers the color of exterior lamps and 
reflective devices.
Section 393.19--Requirements for Turn Signaling Systems
    The FHWA is proposing to revise Sec. 393.19 to make it more 
consistent with FMVSS No. 108 (S5.5.5). Paragraph S5.5.5 provides a 
concise standard that vehicle manufacturers must meet. To ensure 
consistency between FMVSS No. 108 and the FMCSRs, the FHWA would adopt 
the NHTSA standard.
Section 393.20--Clearance Lamps to Indicate Extreme Width and Height
    The FHWA is proposing to remove Sec. 393.20 because the 
requirements for the location and color of clearance lamps are provided 
in Table 1 of Sec. 393.11. The exceptions concerning the mounting of 
clearance lamps currently contained in Sec. 393.20 would be included 
under footnote 15 to Table 1. Illustrations comparable to those 
provided in Sec. 393.20 are already contained in Sec. 393.11.
Section 393.23--Lighting Devices to be Electric
    The FHWA is proposing to amend Sec. 393.23 to incorporate 
terminology which is more consistent with current industry standards 
and practices. With the exception of temporary lamps used on projecting 
loads, lamps would be required to be powered through the electrical 
system of the commercial motor vehicle. The title of Sec. 393.23 would 
be revised to read ``Power supply for lamps'' and the reference to red 
liquid-burning lanterns would be removed as obsolete.
Section 393.24--Requirements for Headlamps and Auxiliary Road Lighting 
Lamps
    The FHWA is proposing to amend Sec. 393.24 to provide a more 
straightforward presentation of the requirements for the mounting of 
headlamps and auxiliary lamps, and to incorporate by reference SAE 
standards applicable to these lamps. Currently Sec. 393.24 allows 
auxiliary and fog lamps to be used provided they meet ``the appropriate 
SAE Standard for such lamps.'' The FHWA would incorporate by reference 
SAE standards J581 Auxiliary Driving Lamps, January 1995, and J583 
Front Fog Lamps, June 1993, for the purpose of establishing more 
specific performance requirements for such lamps. While auxiliary 
driving lamps and fog lamps are not required to be used, performance 
standards should be specified to ensure that the use of such devices 
does not decrease safety.
    A new paragraph is being proposed to address marking of headlamps. 
Paragraph S7.2 of FMVSS No. 108 requires the lens of each headlamp and 
beam contributor manufactured on or after December 1, 1989, to be 
marked. The FHWA proposes to include this requirement under Sec. 393.24 
to ensure that commercial motor vehicles are equipped with original or 
replacement headlamps which meet the requirements of FMVSS No. 108.
    Paragraph (d) of Sec. 393.24, Aiming and intensity, would be 
revised to reference FMVSS No. 108, and SAE standards J581 and J583. 
One of the SAE standards currently referenced in Sec. 393.24(d)--
Electric Headlamps for Motor Vehicles--was canceled by the SAE. The 
other SAE standard, J579 Sealed Beam Headlamp Units for Motor Vehicles, 
is not necessary given the proposed cross-reference to FMVSS No. 108 
and the incorporation by reference of SAE J581 and J583.
Section 393.25--Requirements for Lamps Other Than Headlamps
    To improve the clarity with which the requirements are presented, 
the FHWA is proposing to revise Sec. 393.25 in its entirety. Section 
393.25(a) would provide a concise description of the mounting 
requirements for lamps. Paragraph (b) Visibility, would provide 
technically sound performance standards for all required lamps. 
Currently Sec. 393.25(b) requires lamps to be mounted such that they 
are capable of being seen at distances up to 152.4 meters (500 feet) 
under clear atmospheric conditions during the period when lamps must be 
used as provided by Sec. 392.30. The FHWA determined that Sec. 392.30 
duplicated State and local regulations and removed that requirement on 
November 23, 1994 (59 FR 60319). Also, the FHWA believes the 
performance criteria for lamps are effectively addressed by Sec. 393.11 
which cross-references FMVSS No. 108. Lamps must, at a minimum, meet 
the requirements of FMVSS No. 108 in effect on the date of manufacture 
of the vehicle. FMVSS No. 108 specifies the minimum and maximum 
photometric output values for required lamps. Vehicles not subject to 
FMVSS No. 108 on the date of manufacture would be required to meet the 
visibility requirements specified in the SAE standards proposed for 
incorporation by reference under Sec. 393.25(c).
    The FHWA is proposing to delete Sec. 393.25(d), Certification and 
markings, to make the FMCSRs consistent with FMVSS No. 108. With the 
exception of headlamps and beam contributors, FMVSS No. 108 does not 
require lamps to be marked. Manufacturers are responsible for ensuring 
that their products meet the applicable requirements of FMVSS No. 108 
but the lamps do not have to be marked by the manufacturer to indicate 
that the device meets the standards. In this case, Sec. 393.25(d) sets 
in-service requirements for lamps which are more stringent than the 
manufacturing standards set by the NHTSA. The removal of Sec. 393.25(d) 
would correct this inconsistency.
    The agency is proposing to amend Sec. 393.25(e), Lighting devices 
to be steady-burning, and Sec. 393.25(f), Stop lamp operation, to 
provide more concise statements of the requirements of each. The FHWA 
is proposing to allow exceptions for the use of amber warning lamps 
which meet SAE J595, Flashing Warning Lamps for Authorized Emergency, 
Maintenance and Service Vehicles, January 1990, SAE J845, 360 Degree 
Warning Lamp for Authorized Emergency, Maintenance and Service 
Vehicles, March 1992, or SAE J1318 Gaseous Discharge Warning Lamp for 
Authorized Emergency, Maintenance, and Service Vehicles, April 1986. 
Only Class 2 and Class 3, 360 degree warning lamps and gaseous 
discharge warning lamps would be allowed. Class 1, 360-degree and 
gaseous discharge warning lamps, the primary warning lamps for use on 
authorized emergency vehicles responding to emergency situations, would 
not be allowed. All of these SAE recommended practices would be 
incorporated by reference. In determining the need for this proposal, 
the FHWA notes that Class 2 and 3, 360-degree warning lamps and similar 
non-steady burning lamps are used on many commercial motor vehicles 
which

[[Page 18175]]

transport oversized loads, tow trucks, and certain utility company 
vehicles. Adding these devices to the list of exceptions would prevent 
confusion as to the applicability of Sec. 393.25(e).
    The FHWA is proposing to revise Sec. 393.25(f) to eliminate a 
regulatory inconsistency between Secs. 393.25(f) and 393.49 and to 
simplify the wording of the requirements. Currently, Sec. 393.25(f) 
states that stop lamps on a towing vehicle need not be actuated when 
service brakes are applied to the towed vehicle(s) only. This provision 
is inconsistent with Sec. 393.49, Single valve to operate all brakes. 
When a combination vehicle includes a trailer that is required to be 
equipped with brakes, the braking system must be arranged so that a 
single valve controls the brakes on the towing unit and the towed unit. 
Since the FMCSRs do not allow the towing unit to operate without 
service brakes, and a single valve is required to operate all the 
brakes on the combination, the current wording of Sec. 393.25(f) is 
inconsistent with Sec. 393.49. The proposed revision to Sec. 393.25(f) 
would include language from FMVSS No. 108, S5.5.4, concerning stop lamp 
operation, to ensure consistency between the FMCSRs and the FMVSSs.
Section 393.26--Requirements for Reflectors
    Consistent with the proposed amendments to Sec. 393.25, the FHWA is 
proposing to revise Sec. 393.26 in its entirety. The agency would amend 
Sec. 393.26(a) concerning the mounting of reflectors, to provide 
guidelines comparable to those proposed for Sec. 393.25(a). Paragraph 
(b) would be revised to include a requirement that reflex reflectors on 
projecting loads, vehicles transported in driveaway-towaway operations, 
converter dollies, and pole trailers meet SAE J594--Reflex Reflectors, 
July 1995. The SAE recommended practice would be incorporated by 
reference.
    The current requirement for certification and marking under 
Sec. 393.26(c) would be removed to make the FMCSRs consistent with 
FMVSS No. 108. FMVSS No. 108 does not require that reflectors be marked 
by the manufacturer to indicate that the device meets the standards. 
Paragraph (c) would then be used to incorporate American Society for 
Testing and Materials (ASTM) D4956-90, Standard Specification for 
Retroreflective Sheeting for Traffic Control, as the minimum standard 
for reflective tape used in lieu of reflex reflectors. Retroreflective 
sheeting that conforms to the ASTM standard would generally meet the 
requirements of FMVSS No. 108, S5.1.1.4, concerning the use of 
reflective tape in lieu of reflex reflectors. The performance of the 
reflective sheeting as installed on the vehicle would have to meet the 
geometric visibility requirements under SAE J594, Reflex Reflectors, 
July 1995.
    Paragraph (d) would be revised to more clearly state that 
reflective surfaces or materials other than those required by 
Sec. 393.11 may be used in addition to, but not in lieu of, the 
required reflective devices.
Sections 393.27, 393.28, 393.29, 393.31, 393.32, 393.33--Regulations on 
Electrical Wiring
    The FHWA is proposing to incorporate by reference in Sec. 393.28, 
SAE J1292--Automobile, Truck, Truck-Tractor, Trailer, and Motor Coach 
Wiring, October 1981, which covers basic aspects of performance, 
operating integrity, and service. Section 393.28 would be renamed 
``Wiring systems.'' The guidelines contained in J1292 effectively cover 
the requirements currently addressed by Sec. 393.27, Wiring 
specifications; Sec. 393.28, Wiring to be protected; Sec. 393.29, 
Grounds; Sec. 393.31, Overload protective devices; Sec. 393.32, 
Detachable electrical connections; and Sec. 393.33, Wiring, 
installation. Among the specific topics addressed by the SAE standard 
are insulated cables; conductor termination; conductor splicing; 
conductor grouping; wire assembly construction; wire assembly 
installation and protection; and wiring overload protective devices. 
The SAE standard proposed for incorporation would provide a concise 
presentation of those aspects of commercial vehicle electrical systems 
that should be addressed by the FMCSRs. Sections 393.27, 393.29, 
393.31, 393.32 and 393.33 would be removed.
    The incorporation by reference would also remove certain design 
restrictive language from Sec. 393.28(a)(5) concerning terminals or 
splices above the fuel tank. The FHWA received petitions from the Ford 
Motor Company, Freightliner Corporation, and the Motor Vehicle 
Manufacturers Association (now the American Motor Vehicle Manufacturers 
Association) requesting an amendment to Sec. 393.28(a)(5), which was 
adopted in the December 7, 1988, final rule (53 FR 49380). The 
petitions are available for review in the docket. Each of the petitions 
pointed out that use of the word ``terminal'' combined with ``above'' 
created ambiguity with respect to the proximity of electrical wiring to 
the fuel tanks. Electrical terminals performing various functions, from 
battery terminals (Ford Motor Co.) to relays and switches (Freightliner 
Corporation), are mounted above the fuel tanks. In some instances these 
switches or relays with terminals are mounted 203 mm (8 inches) or more 
above the fuel tank or on the frame rail (in the case of Freightliner 
and Daimler-Benz power units). In the case of Ford power units, the 
fuel tank is specifically designed for battery installation.
    The notice of proposed rulemaking that preceded the final rule 
would have prohibited wiring from being adjacent to any part of the 
fuel system (52 FR 5892, February 26, 1987). The wording in the final 
rule was less restrictive than the proposed language and focused 
specifically on terminals and splices. The FHWA agrees with the 
petitioners, however, that Sec. 393.28(a)(5) is still unnecessarily 
restrictive. The proposed incorporation by reference would provide 
criteria that effectively and safely address the issue of wiring around 
the fuel system of commercial motor vehicles and resolve the 
petitioners' concerns.

Subpart C--Brakes

Section 393.40--Required Brake Systems
    The FHWA is proposing to revise Sec. 393.40 in its entirety to 
present more clearly the requirements contained therein. Generally, all 
vehicles which have been maintained to meet at least the manufacturing 
standards applicable at the time of manufacture will not be affected by 
the proposed revisions. Hydraulic braked and air braked vehicles would 
be required to meet the requirements of FMVSS Nos. 105 and 121, 
respectively, in effect at the time of manufacture. The service, 
parking, and emergency brake requirements for vehicles which were not 
subject to either of the FMVSS brake regulations would be provided by 
references to other applicable sections in subpart C and by the 
requirements currently found under Sec. 393.40(b)(2) and (c).
    With regard to FMVSS No. 105, the FHWA notes that between September 
1, 1975, and October 12, 1976, the standard was applicable to trucks 
and buses. However, from October 12, 1976, to September 1, 1983, it 
covered only passenger cars and school buses. From 1983 to the present 
the standard has applied to trucks and buses. For the purposes of 
Sec. 393.40, the FHWA will use September 2, 1983, as the date for 
determining which hydraulic-braked vehicles must be maintained to meet 
certain requirements under FMVSS No. 105.
    There could be some benefit in requiring vehicles manufactured 
between September 1975 and October

[[Page 18176]]

1976 to meet the requirements of FMVSS No. 105 in effect on the date of 
manufacture. However, the number of these older vehicles still in 
operation is relatively small, and the brake requirements under part 
393 to which these vehicles would continue to be subject should ensure 
safety of operation.
Section 393.41--Parking Brake System
    The December 7, 1988, final rule on part 393 was intended to make 
the parking brake requirements of the FMCSRs consistent with the 
parking brake requirements of FMVSS Nos. 105 and 121. The FHWA has 
since determined that additional changes are necessary. The current 
language only covers air braked vehicles manufactured on or after March 
7, 1990, which are subject to FMVSS No. 121. The wording implies that 
all non-air braked vehicles, irrespective of the date of manufacture, 
and air braked motor vehicles manufactured prior to that date are not 
required to be equipped with parking brakes.
    Prior to the 1988 amendment Sec. 393.41 required that every singly 
driven motor vehicle and every combination of motor vehicles shall at 
all times be equipped with a parking brake system adequate to hold the 
vehicle or combination on any grade on which it is operated under any 
condition of loading on a surface free from ice or snow. The FHWA 
considers the parking brake requirements in effect prior to the 1988 
amendment to provide a more straightforward standard that is easier for 
the industry and State officials to understand.
    The agency is proposing to revise Sec. 393.41 to state clearly that 
every self-propelled commercial motor vehicle (i.e., trucks, truck-
tractors and buses) and every combination of commercial motor vehicles 
must be equipped with a parking brake system adequate to hold the 
vehicle or combination on any grade on which it is to be parked and 
under any condition of loading, on a surface free from ice or snow. 
Commercial motor vehicles which were subject to the parking brake 
requirements of FMVSS Nos. 105 or 121 at the time of manufacture would 
be required to maintain the parking brake systems to meet those 
standards. Motor vehicles which were not subject to either of the FMVSS 
parking brake requirements would have to meet the requirements 
currently found at Sec. 393.41 (b) and (c).
    The proposed revisions to Sec. 393.41 would also address a petition 
for rulemaking from International Transquip Industries, Incorporated 
(ITI) asking the FHWA to clarify the applicable requirements for air-
applied, mechanically-held parking brakes. The petition is available 
for review in the docket. The ITI manufactures an air brake system 
which includes an air-applied, mechanically-held parking brake. The 
parking brake application is initiated by exhausting air off the supply 
line. When the control valve senses the supply line pressure drop, it 
ports air from either the primary or secondary reservoirs at a 
controlled pressure to the brake chambers resulting in an application 
of the brakes. The same supply line pressure signal activates a 
synchronizing device which engages the mechanical pistons immediately 
after the brakes have been applied.
    Section 393.41(b) requires that the parking brake be capable of 
being applied at all times by either the driver's muscular effort, or 
by spring action, or by other energy. In the case of ``other energy,'' 
the accumulation of such energy must be ``isolated from any common 
source and used exclusively for the operation of the parking brake.'' 
This wording has been in effect since 1962 and could be construed as 
requiring a separate reservoir for air-applied, mechanically-held 
parking brakes. Such a requirement is inconsistent with FMVSS No. 121.
    On August 9, 1979, the NHTSA amended FMVSS No. 121 to allow the 
application of the parking brakes by means of service brake air if (1) 
the application could be made when a failure exists in the service 
brake system, and (2) the parking brake is held in the applied position 
by mechanical means (44 FR 46850). Prior to this amendment, an air-
applied, mechanically-held parking brake was required to be applied by 
a separate reservoir. The proposed revision of Sec. 393.41(b) would 
include a cross-reference to the parking brake requirements of FMVSS 
No. 121, thus eliminating any inconsistencies.
    For air braked vehicles which were not subject to FMVSS No. 121 at 
the time of manufacture, Sec. 393.41 would continue to allow the use of 
air-applied, mechanically-held parking brake systems applied by a 
separate reservoir. The motor carrier would have the option of 
modifying the brake system to meet FMVSS No. 121. Air-applied, 
mechanically-held parking brakes which are designed to operate without 
a separate reservoir could be used if the conditions specified in FMVSS 
No. 121 are met.
Section 393.42--Brakes Required On All Wheels
    The agency is proposing to revise Sec. 393.42(b)(3) to clarify the 
exceptions for lightweight trailers and to address brake requirements 
on housemoving dollies, three-axle dollies steered by a co-driver, and 
similar dollies and trailers used for transporting extremely large and 
heavy loads at low speeds.
    As part of the January 27, 1987, final rule on front wheel brakes, 
the FHWA amended the exemption for brakes on lightweight trailers (52 
FR 2801). Prior to the amendment, full trailers, semi-trailers, or pole 
trailers with a gross weight of less than 1,360 kg (3,000 pounds) were 
not required to have brakes provided the weight of the trailer did not 
exceed 40 percent of the weight of the towing unit. The 1987 amendment 
replaced the term ``gross weight'' with ``GVWR'' or gross vehicle 
weight rating.
    While the change to GVWR has certain benefits in terms of applying 
the regulation to situations in which it is not convenient to weigh the 
trailer, the amendment did not adequately address concerns about 
stability and control during braking for trailers that have a GVWR 
greater than 1,361 kg (3,000 pounds), but an actual or gross weight 
less than 1,361 kg when lightly loaded. Under certain circumstances, 
trailers of this weight range may be overbraked resulting in wheel 
lockup or skidding when the trailer is lightly loaded. The FHWA 
believes Sec. 393.42 should be amended to make reference to the gross 
weight. Trailers covered under the current reference to GVWR would be 
covered under the revised exemption provided the vehicle is not loaded 
beyond the manufacturer's weight rating. Trailers with a GVWR in excess 
of 1,361 kg (3,000 pounds) would only be covered by the exemption on 
those occasions when the gross weight of the trailer is 1,361 kg (3,000 
pounds) or less. The proposed language would help to provide a 
performance-based criteria that is easier to understand and enforce.
    Although the exemption concerning lightweight trailers never 
specifically addressed converter dollies, the issue of overbraking on 
unladen converter dollies has been the subject of several requests for 
interpretation of Sec. 393.42(b).
    Converter dollies are generally designed to carry loads of 
approximately 9,072 kg (20,000 pounds) with a brake system sized for 
the fully loaded condition. While the GVWR is greater than 1,360 kg 
(3,000 pounds) the unladen weight is usually 1,360 kg or less. When 
towed behind another motor vehicle, the unladen converter dolly is 
overbraked, with the application of the service brakes causing wheel 
lock-up or skidding.
    In 1990, the NHTSA's Vehicle Research and Test Center (VRTC)

[[Page 18177]]

conducted tests to evaluate the braking and stability of a bobtail 
truck tractor towing an unladen converter dolly. Both the truck tractor 
and the converter dolly were equipped with ABS that could be 
deactivated. The truck tractor was also equipped with an automatic 
front-axle limiting valve (ALV) and a bobtail proportioning valve (BPV) 
that could each be deactivated.
    The tests included 97 km/hour (60 mph) straight-lane braking, 48 
km/hour (30 mph) braking in a 152.4 meters (500 ft) radius curve, and 
56 km/hour (35 mph) straight-lane braking. The 97 km/hour straight-lane 
braking tests were performed on dry concrete (high coefficient of 
friction surface). The braking-in-a-curve tests were performed on wet 
Jennite (low coefficient of friction surface). The 56 km/hour straight-
lane braking was performed on wet polished concrete. The tests used 
``driver best effort'' for the cases in which the ABS was turned off, 
and full-treadle brake applications with the ABS turned on.
    When the brakes on the converter dolly were not connected, stopping 
distances were increased by 12 to 30 percent over those for the bobtail 
tractor without the converter dolly. Also, the absence of braking on 
the converter dolly made locking the drive axles of the tractor easier 
which caused the combination to jackknife. The absence of braking on 
the dolly did, however, prevent locking the wheels and subsequent 
swing-out of the dolly.
    When the brakes on the converter dolly were connected and the 
tractor did not have a bobtail proportioning valve (BPV) system, 
stopping distances on the two wet surfaces were 10 to 25 percent 
shorter than those with the bobtail tractor alone. On the dry surface 
the stopping distances were slightly longer with the dolly brakes 
operational. When the tractor was equipped with a BPV system and the 
dolly brakes were connected, stopping distances were longer on all of 
the test surfaces and in one case by as much as 60 percent.
    There were no stopping distance decreases observed for the tests 
performed on the dry concrete when the converter dolly brakes were 
connected. However, the increases were significantly less than those 
observed when the converter dolly brakes were disconnected.
    While having operable brakes on the unladen converter dolly 
decreased stopping distances in certain cases, two disadvantages were 
observed. If the tractor is equipped with a BPV, hooking up the supply 
(emergency) line to release the parking brakes on the dolly will 
deactivate the BPV and activate the ALV. This is true even if the 
control (service) line is not hooked up to the dolly. This practice 
significantly degrades braking performance, increasing both the 
stopping distance and the chance of a jackknife of the combination 
vehicle. The other disadvantage is that the converter dolly can swing 
out if the wheels lock up.
    Stability and control during braking is an important consideration 
in determining braking requirements for commercial motor vehicles. 
While stopping distances for a bobtail tractor towing an unladen 
converter dolly could be improved in some situations by requiring 
operable dolly brakes, they could be significantly degraded in others. 
When consideration is given to the possibility of the converter dolly 
swinging out as a result of wheel lock up, the FHWA believes the FMCSRs 
should be amended to include an exception to the requirement for 
operable brakes on unladen converter dollies.
    Although regulatory guidance published by the FHWA on November 17, 
1993 (58 FR 60734) stated that Sec. 393.42(b)(3) is applicable to 
unladen converter dollies, this NPRM would create an exception for 
converter dollies under Sec. 393.48, Brakes to be operative. Converter 
dollies are always equipped with brakes. Nevertheless, the air lines 
for the service brakes are sometimes disconnected from the towing 
vehicle when the converter dolly is unladen. Therefore, an exception to 
Sec. 393.42 (the requirement that the converter dolly be equipped with 
brakes) is not necessary. The FHWA is proposing to address the problem 
by amending Sec. 393.48 to provide an exception to the requirement that 
the brakes be operable when the converter dolly is unladen.
    The FHWA notes that with NHTSA's March 10, 1995 (60 FR 13216) final 
rule on antilock braking systems (ABS), the long-term need for this 
exception for unladen converter dollies will diminish. An ABS-equipped 
converter dolly will not have the stability and control problems 
observed with unladen converter dollies that are not equipped with ABS. 
Therefore, converter dollies manufactured on or after March 1, 1998, 
the effective date of the NHTSA requirement for ABS on converter 
dollies, will not be covered by the exception.
    On the subject of housemoving dollies and similar vehicles designed 
to transport extremely large and/or heavy loads, the FHWA is proposing 
an exemption to the requirement for brakes on all wheels based on the 
specialized circumstances under which these motor vehicles are used on 
public roads. Housemoving dollies are only used on public roads when 
transporting houses. Semitrailers are used to transport the dollies 
between jobs. When the dollies are used to transport houses, the 
average speed is less than 32 km/hour (20 mph). Also, escort vehicles 
are generally used when the houses are being moved.
    Similarly, specialized trailers and dollies used to transport 
industrial furnaces, reactors and other heavy cargo are operated at 
speeds less than 32 km/hour (20 mph) and have escort vehicles.
    The FHWA does not believe that safety would be compromised by 
providing an exception to the requirement for brakes on all wheels 
provided the brakes on the towing unit are capable of stopping the 
combination within 12.2 meters (40 feet) from the speed at which the 
vehicle is being operated or 32 km/hour (20 mph), whichever is less.
    The proposed exemption to the requirement for brakes on all wheels 
would also cover the steering axles of three-axle dollies which are 
steered by a co-driver (tillerman) at the rear. These dollies are often 
used to transport concrete or steel beams used for bridges or other 
structures. The loads are often in excess of 30.5 meters (100 feet) in 
length. The front of the load is secured to the power unit with the 
rear of the load secured to the three-axle steerable dolly. A co-
driver, seated in the dolly, operates the steering controls to help 
maneuver the combination vehicle. Although the dolly is equipped with 
brakes via air lines from the towing unit, the steering axle is 
typically overbraked making it difficult for the co-driver to steer the 
dolly. When the dolly is loaded, the steering axle weight rarely 
exceeds 3,402 kg (7,500 pounds).
    The FHWA has no reason to believe that an exemption to the 
requirement for steering axle brakes on these vehicles would degrade 
safety. The vehicles transport unusually long loads, often require 
special permits, and have to operate at reduced speeds. Therefore, the 
agency is proposing to exempt the steering axles of such vehicles from 
the requirement of Sec. 393.42(a) that all wheels be equipped with 
brakes provided the combination of vehicles can meet the stopping 
distance requirements under Sec. 393.52.
Section 393.43--Breakaway and Emergency Braking
    The FHWA is proposing to revise Sec. 393.43(a) to include better 
guidance on the performance requirements for towing vehicle brake 
protection systems. An explicit requirement that the tractor protection 
valve or similar device operate when the air pressure on

[[Page 18178]]

the towing vehicle is between 138 kilopascals (kPa) and 310 kPa (20 psi 
and 45 psi) would be added. This criterion has been used for many years 
during roadside inspections and its inclusion in Sec. 393.43(a) should 
not create a problem for motor carriers.
    The FHWA is proposing to revise Sec. 393.43(b) to codify its 
interpretation of the number of trailer brakes required to apply 
automatically upon breakaway from the towing vehicle. On November 17, 
1993 (58 FR 60734), the FHWA published regulatory guidance which 
indicated that all brakes must be applied upon breakaway. This is 
consistent with the FHWA's November 23, 1977, interpretation (42 FR 
60078). Since FMVSS No. 121 does not specify the number of trailer 
brakes that must apply automatically, it is possible that some trailers 
may be able to meet those performance requirements without having all 
the brakes apply upon breakaway. However, the FHWA believes that most 
trailers would meet the proposed amendment to Sec. 393.43. The FHWA 
specifically requests comments from trailer manufacturers concerning 
this issue.
Sections 393.45 and 393.46--Brake Tubing and Hose
    The FHWA is proposing to revise Sec. 393.45 to address all aspects 
of brake tubing and hoses, including connections, and to remove 
Sec. 393.46. Currently, Sec. 393.45 requires that brake tubing and hose 
be designed and constructed in a manner that ensures proper, adequate, 
and continued functioning of the tubing or hose. The tubing or hoses 
must be long and flexible enough to accommodate without damage all 
normal motions of the parts to which they are attached; be suitably 
secured against chaffing, kinking, or other mechanical damage; and be 
installed in a manner that ensures proper continued functioning and 
prevents contact with the vehicle's exhaust system. Section 393.45 
cross-references FMVSS No. 106 as well as several SAE standards.
    The FHWA would retain most of the current language regarding the 
installation of the brake hoses and the cross-reference to FMVSS No. 
106. The current language regarding the design, material, and 
construction (Secs. 393.45(a) and (b)) would be removed because the 
cross-reference to FMVSS No. 106 addresses manufacturing aspects of 
brake tubing and hoses.
    With the exception of SAE J844--Nonmetallic Air Brake System 
Tubing, the FHWA would eliminate the references to SAE standards on 
brake hoses. Since brake hose manufacturers are required to meet all 
applicable requirements under FMVSS No. 106, the other SAE references 
are unnecessary. The FHWA would incorporate by reference SAE J844 (the 
October 1994 version) for coiled nylon brake tubing because such tubing 
is not required to meet S7.3.6 (length change), S7.3.10 (tensile 
strength), and S7.3.11 (tensile strength of an assembly after immersion 
in water) of FMVSS No. 106. Coiled nylon tubing is exempted from the 
three specific tests through an FMVSS No. 106 cross-reference to 
Sec. 393.45. The proposed incorporation by reference to SAE J844 would 
preserve the current manufacturing standards under FMVSS No. 106 and 
simplify the cross-referencing between FMVSS No. 106 and Sec. 393.45.
    The requirements of Sec. 393.45(c) would be retained because they 
cover aspects of brake hose and tubing installation that are not 
covered in the FMVSSs and otherwise would not be adequately addressed 
in the FMCSRs.
    The FHWA would remove Sec. 393.45(d) because it does not impose any 
specific requirements on motor carriers. As written, the paragraph 
serves as a suggestion or recommendation on the use of metallic and 
nonmetallic brake tubing. Also, given the performance-based 
requirements for brake hose/tubing installation being proposed, the 
current language of Sec. 393.45(d) would be obsolete.
    The proposed changes to Sec. 393.45 would address a petition for 
rulemaking from Imperial Eastman, a brake tubing/hose manufacturer. The 
petition is available for review in the docket. Imperial Eastman 
believes that certain coiled nonmetallic air brake tubing which did not 
meet FMVSS No. 106 was introduced into the market place as a direct 
result of Sec. 393.45. Imperial Eastman believes that prior to the 
December 7, 1988, final rule, Sec. 393.45 was clear and that the 1988 
revision has been interpreted by some as not applying the SAE J844 
requirements to nonmetallic air brake tubing.
    The FHWA believes the proposed cross-reference to FMVSS No. 106 
would make it clear that any brake hose, irrespective of the material 
from which it is manufactured, that meets the requirements of FMVSS No. 
106 would satisfy Sec. 393.45. Also, the revision of Sec. 393.45 would 
have the effect of exempting only coiled nylon tubing which meets SAE 
J844 from the previously mentioned provisions of FMVSS No. 106.
    On the subject of brake tubing and hose connections, the FHWA is 
proposing that all assemblies and end fittings for air, vacuum, or 
hydraulic braking systems be installed so as to ensure an attachment 
free of leaks, constrictions or other conditions which would adversely 
affect the performance of the brake system. Brake tubing and hose 
assemblies and end fittings would be required to meet all applicable 
requirements under FMVSS No. 106, as is currently the case. These 
requirements, currently covered under Sec. 393.46, would be covered 
under Sec. 393.45(e). Since the proposed language for Sec. 393.45 
includes requirements concerning installation, connections and 
attachments, Sec. 393.46 would be removed.
Section 393.47--Brake Lining
    Section 393.47 would be revised to cover brake chambers, slack 
adjusters, linings and pads, drums and rotors. Brake components would 
be required to be constructed, installed, and maintained to prevent 
excessive fading and grabbing. The means of attachment and physical 
characteristics would have to provide for safe and reliable stopping of 
the commercial motor vehicle. To make the requirements of part 393 
consistent with the periodic inspection requirements under appendix G 
to subchapter B, Sec. 393.47 would be amended to require that the 
service brake chambers and spring brake chambers on each end of an axle 
be the same size. The effective length of the slack adjuster on each 
end of an axle would also be required to be the same. In addition, 
minimum requirements on the thickness of linings or pads would be 
specified.
    With regard to linings and pads, the proposed criteria would differ 
from appendix G. Currently, appendix G does not adequately address the 
issue of brake lining thickness on the steering axles of certain 
vehicles (typically those with a GVWR between 4,536 and 14,969 kg 
(10,001 and 33,000 pounds)). This issue was brought to the attention of 
the FHWA by the American Trucking Associations (ATA). The ATA discussed 
front brake lining thickness in a petition for reconsideration of the 
final rule on periodic inspection. The petition is available for review 
in the docket. In its petition, the ATA stated:

    There are two configurations of brake lining used on steering 
axle brakes: blocks (sometimes called pads) and strips. Block lining 
is installed in four segments on the two shoes of each front brake. 
Such lining is typically well over \1/4\ inch thick when new and the 
\1/4\ inch annual inspection criteria is correct for it. Strip 
lining, as the name implies, consists of a continuous band of lining 
installed in two segments, one on each shoe of an individual front 
brake. Certain types of strip lining are only slightly over \1/4\

[[Page 18179]]

inch thick when new. Therefore a \1/4\ inch annual inspection 
criteria is inappropriate.

    The roadside inspection guidelines used by Federal and State 
inspectors have the following criteria to determine if the linings or 
pads of the steering axle of any power unit are worn to the point of 
creating an imminent hazard:

    Lining with a thickness less than \3/16\ inch for a shoe with a 
continuous strip of lining or \1/4\ inch for a shoe with two pads 
for drum brakes or to wear indicator if lining is so marked, or less 
than \1/8\ inch for air disc brakes, and \1/16\ inch or less for 
hydraulic disc, drum and electric brakes.

    The FHWA believes that these guidelines should be added to 
Sec. 393.47 to help motor carriers identify steering axle brake linings 
and pads that are excessively worn. Under a separate rulemaking the 
FHWA will issue a proposal concerning the periodic inspection rule and 
appendix G to subchapter B.
    To address non-steering axle brake lining/pads, the FHWA would 
incorporate into Sec. 393.47 the same criteria currently found in 
appendix G.
    Brake actuator readjustment limits would also be specified under 
Sec. 393.47. The pushrod travel for clamp and roto-chamber type 
actuators would be required to be less than 80 percent of the rated 
strokes listed in SAE J1817--Long Stroke Air Brake Actuator Marking, 
June 1991, or 80 percent of the rated stroke marked on the brake 
chamber by the chamber manufacturer, or the readjustment limit marked 
on the brake chamber by the chamber manufacturer. The pushrod travel 
for Type 16 and 20 long stroke clamp type brake actuators (which are 
not covered under SAE J1817 but for which there are manufacturers' 
recommendations) would be required to be less than 51 mm (2 inches), or 
80 percent of the rated stroke marked on the brake chamber by the 
chamber manufacturer, or the readjustment limit marked on the brake 
chamber by the chamber manufacturer. For wedge brakes, the movement of 
the scribe mark on the lining could not exceed 1.6 mm (\1/16\ inch).
    With regard to brake drums and rotors, the thickness of the drums 
or rotors would have to meet the limits established by the brake drum 
or rotor manufacturer.
Section 393.48--Brakes to be Operative
    The FHWA is proposing to revise Sec. 393.48 (a) and (b) to make the 
requirements easier to understand. The revisions would provide a more 
concise presentation of the requirements.
    With regard to paragraph (c), the FHWA would explicitly address the 
issue of unladen converter dollies and lift axles. Braking on unladen 
converter dollies is covered extensively in discussion of the proposed 
changes to Sec. 393.42. Unladen converter dollies with a gross weight 
of 1,361 kg (3,000 lbs) or less would not be required to have operable 
brakes. Brakes on lift axles would not be required to be capable of 
operation while the lift axle is raised. However, brakes on lift axles 
would have to be operable whenever the lift axle is lowered and the 
tires contact the roadway. Therefore, if an enforcement official 
instructs a driver to lower the lift axle to the ground during an 
inspection, the driver would be required to demonstrate that the brakes 
on that axle are operable. The proposed revisions would essentially 
codify regulatory guidance on these issues.
    In addition, the issue of housemoving dollies, three-axle steerable 
dollies, and similar motor vehicles used to transport extremely heavy 
loads would be addressed to ensure consistency between the proposed 
revisions to Sec. 393.42 and Sec. 393.48.
Section 393.50--Reservoirs Required
    Section 393.50 would be revised to provide a simpler and more 
concise presentation of the reservoir requirements and to cross-
reference FMVSS No. 121. Each air braked truck, truck-tractor, and bus 
manufactured on or after March 1, 1975, would at a minimum be required 
to meet FMVSS No. 121, S5.1.2, in effect on the date of manufacture. 
Trailers manufactured on or after January 1, 1975, would have to meet 
the requirements of FMVSS No. 121, S5.2.1, in effect on the date of 
manufacture. Air braked vehicles manufactured prior to these dates, and 
vacuum braked vehicles would continue to meet the requirements 
currently found at Sec. 393.50.
    The FHWA believes the revision is necessary to indicate clearly 
that a vehicle which is maintained to meet the reservoir requirements 
of FMVSS No. 121 in effect on the date of manufacture would meet the 
requirements under part 393. This is particularly important given the 
NHTSA's January 12, 1995, final rule on FMVSS No. 121 (60 FR 2892). The 
NHTSA amended the reservoir requirements to facilitate the introduction 
of long-stroke brake chambers. For vehicles manufactured on or after 
February 13, 1995, the method for calculating the minimum air reservoir 
capacity is based on either the rated volume of the brake chambers or 
the volume of the brake chambers at the maximum travel of the brake 
pistons or push rods, whichever is less.
Section 393.51--Warning Devices and Gauges
    The agency is proposing to revise Sec. 393.51 to provide better 
guidance on the applicability of the warning device requirements to 
older commercial motor vehicles. Hydraulic braked vehicles manufactured 
on or after September 1, 1975, the effective date of FMVSS No. 105, 
would be required to meet the brake system indicator lamp requirements 
of FMVSS No. 571.105 (S5.3) applicable to the vehicle on the date of 
manufacture. Vehicles manufactured before September 1, 1975, or to 
which FMVSS No. 571.105 was not applicable on the date of manufacture, 
would have to have a warning signal which operates before or upon 
application of the brakes in the event of a hydraulic-type complete 
failure of a partial system. The proposed language would retain all 
current requirements but add the effective date for FMVSS No. 105 and 
identify the specific paragraph within FMVSS No. 105 that covers 
warning devices.
    In addition, the FHWA would insert a note into Sec. 393.51 to 
address the warning device requirements for hydraulic braked trucks and 
buses manufactured between October 12, 1976, and September 1, 1983. 
During this period, FMVSS No. 105 was only applicable to passenger cars 
and school buses. Consequently, manufacturers of hydraulic braked 
trucks and buses were not required to equip those vehicles with a 
warning device to indicate certain types of brake failure. However, 
under the FMCSRs, motor carriers are responsible for having warning 
devices on these vehicles. Since FMVSS No. 105 was not applicable to 
these vehicles at the time of manufacture, the requirements of 
Sec. 393.51 are not in conflict with the NHTSA standard.
    The FHWA has received numerous requests for interpretation from 
motor carriers with vehicles manufactured during this period and not 
equipped with a warning device. Through regulatory guidance, the FHWA 
has indicated that these vehicles are required to be equipped with 
warning devices because Sec. 393.51(b)(2)--which covers hydraulic 
braked vehicles to which FMVSS No. 105 was not applicable at the time 
of manufacture--was in effect prior to October 12, 1976, and has 
remained in effect ever since. Therefore, the agency is essentially 
proposing to codify the regulatory guidance concerning warning devices 
on these vehicles.
    On the subject of air braked vehicles, the FHWA is proposing to 
revise Sec. 393.51(c) to include reference to the

[[Page 18180]]

March 1, 1975, effective date of FMVSS No. 121 for power units. The 
specific paragraphs within FMVSS No. 121 which address the pressure 
gauge and warning signal requirements would also be included.
    Vehicles which are not required to meet the requirements of FMVSS 
No. 121 would have to be equipped with a pressure gauge, visible to a 
person seated in the normal driving position, which indicates the air 
pressure (in kilopascals (kPa) or pounds per square inch (psi)) 
available for braking; and, a warning signal that is audible or visible 
to a person in the normal driving position and provides a continuous 
warning to the driver whenever the air pressure in the service 
reservoir system is at 379 kPa (55 psi) and below, or one-half of the 
compressor governor cutout pressure, whichever is less.
    With regard to commercial motor vehicles with hydraulic brakes 
applied or assisted by air or vacuum, the FHWA is proposing to revise 
Sec. 393.51(e) to make it applicable only to hydraulic braked vehicles 
which were not subject to the FMVSS No. 105 at the time of manufacture. 
The amendment would eliminate the inconsistency between the warning 
device requirements of FMVSS No. 105 and Sec. 393.51(e). Currently, 
Sec. 393.51(e) requires a warning device for the hydraulic portion of 
the brake system as well as a warning device for the air or vacuum 
portion of the brake system, irrespective of the applicability of FMVSS 
No. 105. However, FMVSS No. 105 does not require a warning device for 
the air or vacuum portion of these hydraulic brake systems. The FHWA 
believes the Sec. 393.51(b) cross-reference to FMVSS No. 105 provides 
effective requirements for warning devices on hydraulic braked vehicles 
subject to that standard at the time of manufacture. A requirement for 
an additional warning device for the air or hydraulic portion of the 
brake system of these vehicles is not necessary.
    For air-assisted or vacuum-assisted hydraulic braked vehicles which 
were not subject to FMVSS No. 105, the FHWA would retain the current 
requirements for a warning device for the hydraulic portion of the 
brake system and a warning device for the air or vacuum portion of the 
brake system. Section 393.51(e) would continue to require that the 
hydraulic portion of the vehicle meet the requirements of 
Sec. 393.51(b) and that the air or vacuum portion of the brake system 
meet the applicable requirements of paragraph (c) or (d).
    The FHWA notes that commercial motor vehicles equipped with air-
over-hydraulic brake systems are classified as air braked vehicles and, 
as such, would be required to meet the applicable warning device and 
pressure gauge requirements for air braked vehicles.
    With regard to the proposed amendments to Sec. 393.51(e), the FHWA 
specifically requests comments on the need for retaining the warning 
device requirement for the air or vacuum portion of air- and vacuum-
assisted hydraulic brake systems. The FHWA also requests information 
from vehicle manufacturers as to the number of commercial motor 
vehicles manufactured annually with such brake systems or the last 
model year for which they produced vehicles equipped with this type of 
brake system.
    Finally, the FHWA is proposing to reinstate one of the exemptions 
that were removed by the December 7, 1988, final rule on part 393. The 
1988 rule revised Sec. 393.51 by removing paragraph (g), which 
contained two exemptions that were considered obsolete with the 
adoption of the definition of a commercial motor vehicle. The 
exemptions covered buses with a seating capacity of 10 persons or less 
(including the driver), and two-axle property-carrying vehicles that 
were either manufactured before July 1, 1973, or had a GVWR of 4,536 kg 
(10,000 pounds) or less.
    From a practical standpoint, all two-axle property-carrying 
vehicles with a GVWR of 4,536 kg or less, and equipped with air, 
vacuum, or air-assisted or vacuum-assisted hydraulic brake systems were 
exempted irrespective of the date of manufacture. Generally, these 
vehicles are only subject to the FMCSRs only when transporting 
hazardous materials in a quantity that requires placarding or when 
towing another vehicle such that the gross combination weight rating 
exceeds 4,536 kg (10,000 pounds).
    Therefore, the FHWA believes that the exemption for certain two-
axle property-carrying vehicles should be reinstated but limited to 
two-axle property-carrying vehicles manufactured before July 1, 1973. 
Since the group of vehicles covered by the exemption represents a small 
segment of the total population of vehicles that fall under the FHWA's 
jurisdiction, and these vehicles have either reached, or will soon 
reach the end of their service life, and these vehicles were previously 
exempted, the proposed reinstatement should not reduce safety on the 
highways.
    The FHWA is not proposing to reinstate the exemption for buses with 
a seating capacity of 10 persons or less because these vehicles are 
generally not subject to the FMCSRs.

Subpart D--Glazing and Window Construction

Section 393.60--Glazing in Specified Openings
    The FHWA is proposing that glazing material used in windshields, 
windows and doors of commercial motor vehicles manufactured on or after 
December 25, 1968, be required at a minimum to meet the requirements of 
FMVSS No. 205 in effect on the date of manufacture of the vehicle. The 
glazing material would be required to be marked accordingly. The cross-
reference to FMVSS No. 205 would replace the current reference to 
Safety Code for Safety Glazing Materials for Glazing Motor Vehicles 
Operating on Land Highways. Since FMVSS No. 205 incorporates this 
publication by reference, the requirements for the glazing material 
would not be affected.
    Section 393.60 would also be revised to include a requirement that 
each bus, truck, and truck-tractor be equipped with a windshield. Each 
windshield or portion of a multi-piece windshield would be required to 
be mounted using the full periphery of the glazing material.
    With regard to coloring or tinting of windshields and side windows, 
the FHWA would revise the current requirements to codify regulatory 
guidance on this topic. Coloring or tinting of windshields and the 
windows to the immediate right and left of the driver would be allowed 
provided the parallel luminous transmittance through the colored or 
tinted glazing is not less than 70 percent of the light at normal 
incidence in those portions of the windshield or windows which are 
marked as having a luminous transmittance of at least 70 percent.
    The current reference to tinting applied at the time of manufacture 
would be removed. The restrictions on tinting would be focused solely 
on ensuring that the glazing material allows light transmittance at a 
level requisite for driving visibility and not the regulation of when 
the tinting is applied.
    The agency is proposing to revise Sec. 393.60(c) concerning 
restrictions on the use of vision-reducing matter on windshields. On 
March 6, 1995, the FHWA granted a petition from the Commonwealth of 
Kentucky, and Heavy Vehicle Electronic License Plate, Inc. (HELP) 
requesting a waiver from the requirements of Sec. 393.60(c) to allow 
mounting of an automatic vehicle identification transponder at the 
upper border of the windshields of commercial motor vehicles ( 60 FR 
12146). The waiver was necessary because Sec. 393.60(c) prohibits the 
operation of a

[[Page 18181]]

commercial motor vehicle with vision-reducing matter covering any 
portion of the windshield with certain exceptions for decals required 
by law and affixed to the bottom of the windshield.
    In evaluating the requests for waivers to Sec. 393.60(c), the FHWA 
reviewed automotive engineering recommended practices, the NHTSA's 
FMVSSs, and recent research concerning driver's field of view. The 
agency also examined current commercial motor vehicle cab designs 
related to placement of interior mirrors and sun visors which occupy 
approximately the same space proposed for the transponder. Based upon 
the information obtained from this review, the FHWA concluded that a 
transponder mounted at the approximate center of the top of the 
windshield would be extremely unlikely to create a situation 
inconsistent with the safe operation of a commercial motor vehicle. 
This location is well outside the area recommended for windshield wiper 
sweep under the SAE recommended practice J198, Windshield Wiper 
Systems--Trucks, Buses, and Multipurpose Vehicles, and the area 
recommended for windshield defrosting under J342, Windshield Defrosting 
Systems Performance Guidelines--Trucks, Buses, and Multipurpose 
Vehicles. The findings of recent research reports on the subject also 
suggested that the location of an object, such as a transponder device, 
near the upper margin of a windshield is unlikely to have any effect on 
a driver's ability to observe nearby objects, such as pedestrians.
    For the reasons presented in the notice granting the waiver, the 
agency is proposing to allow the installation of antennas, 
transponders, and similar devices in the upper margin of windshields. 
These devices could not be placed lower than 152 mm (6 inches) from the 
upper edge of the windshield, must be outside the area swept by the 
windshield wipers, and must be outside the driver's sight lines to the 
road and highway signs or signals. The proposed amendment would codify 
the March 6, 1995, waiver and help to promote the use of advanced 
technologies to improve the efficiency and safety of operation of 
commercial motor vehicles.
    With regard to the current limitations on the placement of decals 
and stickers at the bottom of the windshield, the FHWA would adopt a 
performance-based requirement that decals required by law must not 
obstruct the driver's view of the road, or traffic signs. Since the 
decals in question are required by Federal or State law, the FHWA does 
not believe it is necessary to retain the 11.4 cm (4-\1/2\ inch) -
restriction on the distance from the bottom of the windshield. It is 
anticipated that the agencies responsible for specifying the location 
of such decals will exercise discretion and limit the use of decals in 
the windshield area.
Sections 393.61, 393.62, 393.63, 393.92--Window Construction and 
Emergency Exits
    Section 393.61 would be revised to cover only truck and truck 
tractor window construction. Window construction for buses (or 
emergency exits) would be covered under Sec. 393.62. The prohibitions 
on window obstructions currently found at Sec. 393.62 would be 
addressed along with the emergency exits requirements. The provisions 
of Sec. 393.63 (Windows, markings) and Sec. 393.92 (Buses, marking 
emergency doors) would also be covered under the revised rule on 
emergency exits. Sections 393.63 and 393.92 would be removed.
    In Sec. 393.61, the FHWA would remove the reference to an ellipse 
in determining the minimum area of a truck or truck-tractor window. The 
rectangular dimensions currently provided appear to be sufficient. 
Also, the rectangular dimensions provide the most practical and 
enforceable criteria.
    As for emergency exits on buses, the FHWA would revise its cross-
references to FMVSS No. 217 so that motor carriers and enforcement 
officials will have better guidance on the applicability of NHTSA's 
recent amendments to those buses subject to the FMCSRs. On November 2, 
1992, FMVSS No. 217 was amended to require that the minimum emergency 
exit space on school buses be based upon the seating capacity of each 
bus (57 FR 49413). The NHTSA final rule took effect September 1, 1994.
    Further, in a separate notice, the NHTSA proposed allowing non-
school buses to meet either the non-school bus requirements or the new 
upgraded school bus requirements (57 FR 49444, November 2, 1992). The 
NHTSA issued the final rule on May 9, 1995 (60 FR 24562).
    The FHWA has carefully reviewed the NHTSA rulemakings and 
determined that the FMCSRs should be amended to address the November 2, 
1992, and May 9, 1995, final rules. The FHWA is proposing to allow the 
upgraded school bus emergency exit requirements on buses subject to the 
FMCSRs so that motor carriers would be afforded the same flexibility 
given to manufacturers under FMVSS No. 217.
    Buses manufactured on or after September 1, 1994, and having a GVWR 
of 4,536 kg (10,000 pounds) or less must meet the emergency exit 
requirements of FMVSS No. 217 (S5.2.2.3) in effect on the date of 
manufacture. Generally, these buses would only be subject to the FMCSRs 
when towing a trailer. If the gross combination weight rating (GCWR) 
for the bus and trailer is greater than 4,536 kg, and the combination 
is operated in interstate commerce, the emergency exit requirements 
proposed would be applicable. An example would be a small bus operated 
by a private motor carrier of passengers.
    For buses with a GVWR of more than 4,536 kg (10,000 pounds), the 
FHWA would require that they have emergency exits which meet the 
applicable emergency exit requirements of FMVSS No. 217, S5.2.2 (the 
non-school bus requirements) or S5.2.3 (the upgraded school bus 
requirements) in effect on the date of manufacture. The provision for 
buses with a GVWR greater than 4,536 kg would incorporate NHTSA's final 
rules.
    For buses manufactured on or after September 1, 1973, but before 
September 1, 1994, the FHWA is proposing that each bus (including a 
school bus used in interstate commerce for non-school bus operations) 
with a GVWR of more than 4,536 kg (10,000 pounds) meet the requirements 
of FMVSS No. 217, S5.2.2, in effect on the date of manufacture. Buses 
with a GVWR of 4,536 kg (10,000 pounds) or less would have to meet the 
requirements of FMVSS No. 217, S5.2.2.3, in effect on the date of 
manufacture.
    Section 393.62 would be revised to include a paragraph on emergency 
exit identification. Each bus and each school bus used in interstate 
commerce for non-school bus operations, manufactured on or after 
September 1, 1973, would have to meet the applicable emergency exit 
identification or marking requirements of FMVSS No. 217, S5.5, in 
effect on the date of manufacture. Buses (including school buses used 
in interstate commerce for non-school bus operations) would have to be 
marked ``Emergency Exit'' or ``Emergency Door'' followed by concise 
operating instructions describing each motion necessary to unlatch or 
open the exit located within 152 mm (6 inches) of the release 
mechanism.
    The emergency exit requirements for buses manufactured before 
September 1, 1973, would be revised to provide requirements which are 
easier to understand and enforce. These buses would have to have either 
laminated safety glass or push-out windows. The regulation would more 
clearly state that laminated safety glass would, at a minimum, be 
required to meet Test No. 25, Egress, of the American National

[[Page 18182]]

Standards Institute (ANSI), Safety Code for Safety Glazing Materials 
for Glazing Motor Vehicles Operating on Land Highways, ANSI Z26.1-1990. 
The FHWA would incorporate the ANSI document by reference.
    With regard to push-out windows, the requirements would be revised 
to adopt certain provisions of FMVSS No. 217. Each push-out window 
would be required to be releasable by operating no more than two 
mechanisms and allow manual release of the exit by a single occupant. 
For mechanisms which require rotary or straight (parallel to the 
undisturbed exit surface) motions to operate the exit, the amount of 
force required to release the exit could not exceed 89 Newtons (20 
pounds). For exits which require a straight motion perpendicular to the 
undisturbed exit surface, the amount of force could not exceed 267 
Newtons (60 pounds).
    The FHWA believes that the force requirements being proposed should 
not present a problem for motor carriers and that older buses with 
emergency exits that cannot meet these basic performance requirements 
should have the emergency exit release mechanisms replaced. This 
proposal should not be construed as an attempt to require that the 
entire emergency exit be replaced, only release mechanisms which do not 
meet the criteria.
    Lastly, the FHWA would codify its regulatory guidance on buses used 
for the transportation of prisoners. An exception to the emergency exit 
requirements would be included for buses used exclusively for the 
transportation of prisoners.

Subpart E--Fuel Systems

Section 393.67--Liquid Fuel Tanks
    The FHWA proposes to revise paragraph (a) to indicate that the fuel 
tank requirements apply not only to tanks containing or supplying fuel 
for the operation of commercial motor vehicles, but includes tanks 
needed for the operation of auxiliary equipment installed on, or used 
in connection with commercial motor vehicles. Section 393.65(a), the 
requirements for fuel systems, contains similar language and the FHWA 
believes the applicability statement of Sec. 393.67 should be amended 
to be consistent with Sec. 393.65.
    The FHWA also proposes to revise Sec. 393.67(d) and (e) to include 
the information currently presented in a footnote to the section. As 
indicated by the footnote, the fuel tank tests specified by Sec. 393.67 
are a measure of performance only. Alternative procedures which assure 
that the fuel tank meets the performance criteria may be used. However, 
this footnote is often overlooked. Including the text of the footnote 
in paragraphs (d) and (e) would help to prevent further confusion.
    In addition, the FHWA proposes to correct an error in 
Sec. 393.67(f)(2). Currently, each liquid fuel tank manufactured on or 
after July 1, 1988, must be marked with the manufacturer's name. The 
July 1, 1988, date is incorrect. The FHWA intended that the date read 
July 1, 1989, approximately 120 days after the March 7, 1989, effective 
date of the December 7, 1988, final rule on part 393.
Section 393.68--Compressed Natural Gas Fuel Containers
    The FHWA is proposing to create a new section to address 
requirements for compressed natural gas (CNG) fuel containers. Section 
393.68 would cross-reference the NHTSA's new requirements for CNG 
containers, FMVSS No. 304, Compressed Natural Gas Fuel Container 
Integrity (September 26, 1994, 59 FR 49010). Under FMVSS No. 304, which 
is applicable to all CNG containers manufactured on or after March 26, 
1995, CNG fuel containers must meet a pressure cycling test which 
evaluates the container's durability, a burst test to measure its 
strength, and a fire test to ensure adequate pressure relief 
characteristics. The rule also specifies labeling requirements.
    The FHWA has reviewed the NHTSA requirements and determined that 
all commercial motor vehicles manufactured on or after March 26, 1995, 
and equipped with CNG fuel tanks, should be required to be maintained 
to meet the applicable requirements of FMVSS No. 304.

Subpart F--Coupling Devices and Towing Methods

Section 393.70--Coupling Devices and Towing Methods, Except for 
Driveaway-Towaway Operations
    Currently Sec. 393.70(d) provides requirements for the attachment 
of safety devices in case of tow-bar failure. If two chains or cables 
are attached to the same point on the towing vehicle, or if a bridle or 
a single chain or cable is used, the point of attachment must be on the 
longitudinal centerline of the towing vehicle. A single safety device, 
other than a chain or cable, must also be attached to the towing 
vehicle at a point on its longitudinal centerline.
    Western Trailers petitioned the FHWA to amend Sec. 393.70(d)(8) to 
allow safety devices to be attached as close as practicable to the 
longitudinal centerline of the towing vehicle. The petition is 
available for review in the docket. The petitioner argued that because 
the pintle hook is mounted on the longitudinal centerline of the towing 
vehicle, there is no practical centerline mounting position for the 
safety chain/cable attachment except upon or above the pintle hook 
itself.
    In reviewing the history of the requirements for safety chains from 
1941 through the present, the FHWA notes that a certain amount of 
flexibility had been allowed such that chains could be attached as 
close as ``practicable'' to the centerline. Although the current 
requirements, adopted on October 11, 1972 (37 FR 21439), do not appear 
to have created problems for other carriers, the FHWA agrees that there 
is a need to reexamine the requirement and eliminate any unnecessary 
restrictions. To that end, the FHWA believes that specifying the 
location for attachment point of the safety devices with such precision 
is unnecessarily design-restrictive.
    The attachment of the safety devices to a point as close as 
``practicable'' to the centerline is needed to ensure that the 
combination of vehicles will maintain as much stability as possible in 
the event the coupling device fails. However, given the size and weight 
of a typical commercial motor vehicle, there is little technical 
justification for prohibiting attachment of the safety devices at a 
point within a few centimeters (or inches) off the centerline. In fact, 
failure of the coupling device at its centerline point of attachment to 
the towing vehicle might damage the anchor point of the safety chains, 
possibly resulting in complete separation of the trailer.
    In addition, the current language of Sec. 393.70(d)(8) may, under 
some circumstances, be inconsistent with Sec. 393.70(d)(1), which 
prohibits the attachment of the safety device to the pintle hook or any 
other device on the towing vehicle to which a tow-bar is attached.
    The previous provisions of Sec. 393.70 provided a performance-based 
requirement while ensuring the safety of operation of the combination 
of vehicles. The language used, however, may have been difficult to 
enforce, in that ``practicability'' is a subjective term. This 
generally results in differences of opinion between vehicle 
manufacturers, motor carriers, and Federal and State enforcement 
officials as to what constitutes compliance.
    An amended rule that allows the attachment point to be offset no 
more than a certain distance from the longitudinal centerline would 
provide flexibility without adversely affecting the tracking of the 
towed unit in the

[[Page 18183]]

event of a pintle hook failure. The FHWA notes that the safety device 
is only intended to keep the combination of vehicles together if the 
pintle hook or other coupling device fails and then only for a brief 
period until the driver brings the vehicle to a safe stop. Therefore, 
the proposed change should not affect the safety of operation of the 
vehicles.
    The FHWA is proposing to allow safety chains or cables to be 
attached to the longitudinal centerline or within 152 mm (6 inches) to 
the right of the longitudinal centerline on the towing vehicle. The 
proposal would be applicable when (1) two chains or cables are attached 
to the same point on the towing vehicle; (2) a bridle or a single chain 
or cable is used; or (3) a single safety device is used.
    Given the wide variety of vehicle configurations and the condition 
of loading at the time of a potential tow-bar or pintle hook failure, 
the current design-restrictive requirement does not appear to ensure a 
greater degree of safety than the proposed revision. Allowing the 
safety device to be no more than 152 mm (6 inches) from the 
longitudinal centerline should provide additional safety benefits in a 
few cases without changing the level of safety guaranteed by the 
current centerline requirement in other cases. It would also result in 
a requirement that is more performance-based and less design-
restrictive.
    The FHWA specifically requests comments on the following issues:
    1. Although the petitioner did not specify a maximum offset 
distance from the longitudinal centerline for the safety device 
attachment point, the FHWA believes that a distance of 152 mm (6 
inches) is consistent with the diagrams submitted by the petitioner. 
Would allowing a 152 mm (6 inch) offset provide adequate flexibility to 
motor carriers and trailer manufacturers without adversely affecting 
the safety of operation of certain combination vehicles?
    2. The petitioner believes that safety chains should be allowed to 
be offset only to the right side of the longitudinal centerline in 
order to prevent the towed vehicle from striking oncoming traffic on 
undivided highways. In cases where a single safety device is used, and 
it is not practical to attach it to a point at the longitudinal 
centerline, should the offset be restricted to the right side, or 
should it be permitted to be on either side?
Section 393.71--Coupling Devices and Towing Methods, Driveaway-Towaway 
Operations
    Section 393.71(a) currently prohibits the use of more than one tow-
bar in any combination of vehicles. Section 393.71(g)(2) indicates that 
coupling devices such as those used for towing house trailers and 
employing ball and socket connections shall be considered as tow-bars. 
However, the broad classification of ball and socket connections as 
tow-bars is not consistent with the definitions of the Society of 
Automotive Engineers. As a result, the use of more than one ball-and-
socket connection in a combination of vehicles is prohibited. This 
situation requires clarification.
    The FHWA considers the stability and control of a combination 
vehicle using multiple ball-and-socket connections no better than that 
of a combination using multiple tow-bars. Given that the stability and 
control would, at best, be comparable to a towing method which is 
prohibited, the FHWA is proposing that Sec. 393.71(a)(2) be revised to 
prohibit the use of more than one tow-bar and/or ball-and-socket 
coupling device in any combination. Section 393.71(g)(2) would be 
removed.
    To improve the consistency between Sections 393.70 and 393.71, the 
FHWA is proposing to amend Sec. 393.71(b) by adding a new provision 
addressing weight distribution of towing and towed vehicles for saddle-
mount combinations.
    Sections 393.70(b)(3), 393.71(b)(2) and 393.71(c)(3) address the 
proper weight distribution and require that the coupling arrangement be 
such that it does not unduly interfere with the steering, braking, and 
maneuvering of the combination of vehicles. Section 393.70(b)(3) covers 
the use of fifth wheels for non-driveaway-towaway operations and 
Secs. 393.71(b)(2) and (c)(3) cover full-mounted vehicles in driveaway-
towaway operations. Section 393.71(b) does not, however, explicitly 
require that the arrangement of the saddle-mounted vehicles be such 
that it does not unduly interfere with the steering, braking and 
maneuvering of the combination of vehicles. The references to undue 
interference with steering, braking, and maneuvering in Secs. 393.70 
and 393.71 suggest that such requirements are generally intended for 
any vehicle configuration covered by these sections. Through regulatory 
guidance the agency has indicated that saddle-mounted vehicles are to 
be arranged such that the gross weight of the vehicles is properly 
distributed to prevent the conditions currently covered by 
Secs. 393.70(b)(3), 393.71(b)(2) and 393.71(c)(3). The FHWA would 
codify this guidance in Sec. 393.71(b)(3).
    The FHWA is proposing to revise Sec. 393.71(g) to remove obsolete 
language and provide more technically sound guidance on towing methods. 
Section 393.71(g)(1) currently requires the use of a tow-bar or saddle-
mount connections for all vehicles towed in driveaway-towaway 
operations. This is inappropriate for towing semitrailers designed to 
be coupled to a fifth wheel. Through regulatory guidance the agency has 
allowed the use of a fifth wheel. The agency would codify this guidance 
by revising Sec. 393.71(g) to explicitly allow the use of a fifth 
wheel.

Subpart G--Miscellaneous Parts and Accessories

Section 393.75--Tires
    The FHWA is proposing to amend Sec. 393.75(e) in order to make the 
requirements easier to understand. Section 393.75(e) prohibits the use 
of regrooved tires which have a load carrying capacity greater than 
that of 8.25-20 8 ply-rating tires, but does not specify the load range 
rating for this tire. According to the Tire and Rim Association's 1996 
Year Book, an 8.25-20 bias ply tire has a maximum load carrying 
capacity of 2,232 kg (4,920 pounds) at 793 kPa (115 psi) cold inflation 
pressure. This maximum capacity applies to tires of load range G. Tires 
with the load range of E and F have maximum load carrying capacities of 
1,837 kg (4,050 pounds) and 2,041 kg (4,500 pounds), respectively. The 
FHWA is proposing to use the 2,232 kg limit under Sec. 393.75.
    The difference in load carrying capacity between a tire rated load 
range E and one rated load range G is 395 kg (870 pounds). In the 
absence of tire overloading, the difference in the amount of front axle 
loading between an axle equipped with load range E tires and a front 
axle equipped with load range G tires would be 790 kg (1,740 pounds). 
There is no apparent safety benefit from adopting the more stringent 
limit of load range E for regrooved tires. Therefore, the use of a 
regrooved tire with a load carrying capacity equal to or greater than 
2,232 kg (4,920 pounds) would be a violation of Sec. 393.75(e) if used 
on the front wheels of a truck or truck tractor.
    The FHWA notes that a radial ply tire of the same size and load 
range (i.e., 8.25R20) has the same load carrying capacity but at 827 
kPa (120 psi) cold inflation pressure. Since the prohibition is based 
on load carrying capacity, the FHWA is proposing to replace the

[[Page 18184]]

reference to a specific tire size with the 2,232 kg (4,920 pound) value 
currently listed in the Tire and Rim Association's publication.
Section 393.78--Windshield Wipers
    The FHWA is proposing that Sec. 393.78 be revised to cross-
reference FMVSS No. 104. The NHTSA requirement has been in effect since 
December 1968. Since vehicle manufacturers have been required to meet 
the requirements since 1968, the FHWA does not believe that motor 
carriers who have maintained their commercial motor vehicles should 
have any problem complying with the proposed revision. As for motor 
vehicles manufactured before December 1968, they would be required to 
be equipped with a power-driven windshield wiping system with at least 
two wiper blades, one on each side of the centerline of the windshield. 
Motor vehicles which depend upon vacuum to operate the windshield 
wipers would have to have the wiper system constructed and maintained 
such that the performance of the wipers will not be adversely affected 
by a change in the intake manifold pressure. The requirements for 
vehicles manufactured before December 1968 were originally established 
by the Interstate Commerce Commision and were applicable to vehicles 
manufactured on and after June 30, 1953.
    The FHWA is proposing to remove the exemption for the towing 
vehicle in a driveaway-towaway operation because there appears to be no 
justification for allowing a vehicle to be driven without both 
windshield wipers in proper working order. The proposed change should 
not result in an increased economic burden on the motor carrier 
industry.
Section 393.79--Windshield Defrosting Device
    Section 393.79 would be revised to cross-reference FMVSS No. 103. 
Vehicles manufactured on or after December 25, 1968, would be required 
to meet the requirements in effect on the date of manufacture. Vehicles 
manufactured before December 25, 1968, would be required, at a minimum, 
to be equipped with a means for preventing the accumulation of ice, 
snow, frost, or condensation to obstruct the driver's view through the 
windshield while the vehicle is being driven.
    In addition, the exemption for the towing vehicle in a driveaway-
towaway operation would be removed. There is no justification for 
allowing a vehicle to be driven without a windshield defrosting device 
in proper working order.
Section 393.82--Speedometer
    Section 393.82 requires that every bus, truck, and truck-tractor be 
equipped with a speedometer indicating speed in miles per hour. The 
rule requires the speedometer to be operative with ``reasonable 
accuracy.'' Appendix A to subchapter B (prior to its removal from the 
FMCSRs on November 23, 1994 (59 FR 60319)) interpreted as 
``reasonable'' an accuracy of plus or minus 8 km/hr (5 mph) at a speed 
of 80 km/hr (50 mph). The interpretation indicated that accuracy within 
these limits is sufficient for a professional driver to ascertain the 
true speed of the vehicle. The FHWA is proposing to include this 
accuracy limit in Sec. 393.82 to make the requirement easier to 
understand. The FHWA is also proposing to remove the driveaway-towaway 
exemption to the speedometer requirements because there is no 
justification for allowing a vehicle to be driven without a speedometer 
in proper working order. The proposed changes should not result in an 
increased economic burden on the motor carrier industry.
Section 393.87--Flags on Projecting Loads
    Section 393.87 would be revised to make the requirements consistent 
with the American Association of State Highway and Transportation 
Officials's (AASHTO) Guide for Maximum Dimensions and Weights of Motor 
Vehicles and for the Operation of Nondivisible Load Oversize and 
Overweight Vehicles, GSW-3, 1991. The AASHTO publication provides 
guidance on the use of warning flags for vehicles and loads which 
exceed legal width or length, or which have a rear overhang in excess 
of the legal limit. The AASHTO guidelines call for the use of red or 
orange fluorescent warning flags which are at least 457 mm (18 inches) 
square. Since the AASHTO guide appears to cover the majority of the 
cases to which the current rule would be applicable, and represents a 
consensus of State and industry practices, the FHWA proposes to revise 
Sec. 393.87 to adopt certain provisions of those guidelines.
    Commercial motor vehicles transporting loads which extend beyond 
the sides by more than 102 mm (4 inches) or more than 1,219 mm (4 feet) 
beyond the rear would be required to have the extremities of the load 
marked with red or orange fluorescent warning flags. Each warning flag 
would be required to be at least 457 mm (18 inches) square as opposed 
to the current requirement of 305 mm (12 inches) square.
    With regard to the number of flags and their positions, a single 
flag at the extreme rear would be required if the projecting load is 
610 mm (2 feet) wide or less. Two warning flags would be required if 
the projecting load is wider than 610 mm. Flags would be required to be 
positioned to indicate maximum width of loads which extend beyond the 
sides and/or rear of the vehicle.
Section 393.94--Vehicle Interior Noise Level
    The FHWA is taking this opportunity to clarify and simplify its 
regulation concerning the applicability of the interior noise levels in 
commercial motor vehicles. Section 393.94(a) and (d) make reference to 
certain vehicles manufactured before October 1, 1974, and grant motor 
carriers until April 1, 1975, to comply with the regulation. For 
vehicles operated wholly within Hawaii, carriers were given until April 
1, 1976, to comply. Since these deadlines have passed, the FHWA is 
proposing to delete the references from Sec. 393.94.
    In addition, the FHWA is proposing to update the reference to the 
American National Standards Institute (ANSI) specifications for sound 
level meters. Currently, Sec. 393.94 references the 1971 version of 
ANSI S1.4, Specification for Sound Level Meters. The FHWA would 
incorporate by reference the 1983 version and remove the footnote to 
paragraph (c). Information on the availability of the ANSI document 
would be covered under Sec. 393.7.
Section 393.95 Emergency Equipment on All Power Units
    The FHWA is proposing to eliminate the reference to lightweight 
vehicles in paragraph (a). The term became obsolete when the agency 
implemented the requirements of the Motor Carrier Safety Act of 1984 
and limited the applicability of the part 393 to ``commercial motor 
vehicles'' as defined in that statute (53 FR 18042, May 19, 1988). 
Sections 393.95(a)(2)(i) and (a)(2)(ii) would also be amended to remove 
obsolete references to vehicles equipped with fire extinguishers prior 
to July 1, 1971, and January 1, 1973, respectively. While some of these 
vehicles are still in operation, it is unlikely that the motor carriers 
would still be using fire extinguishers that are more than 20 years 
old.
    The FHWA would revise Sec. 393.95 by removing the specifications 
for bidirectional warning triangles manufactured prior to January 1, 
1974. Such triangles are already prohibited on

[[Page 18185]]

any vehicle manufactured on or after January 1, 1974. Therefore, only 
those carriers operating commercial motor vehicles manufactured before 
January 1, 1974, and equipped with warning triangles manufactured 
before that date, would be affected.
    The FHWA would revise the requirements on the mounting of fire 
extinguishers to provide more specific guidance. Fire extinguishers 
would be required to be securely mounted to prevent sliding, rolling, 
or vertical movement relative to the motor vehicle. Currently, 
Sec. 393.95(a)(1) states only that the extinguisher be securely 
mounted.
    With regard to extinguishing agents, the agency is proposing to 
replace the reference to the Underwriters Laboratories'(UL) 
Classification of Comparative Life Hazard of Gases and Vapors. The UL 
study was conducted in the 1950's and is considered obsolete 
information. The UL has recommended that the FHWA consider referencing 
the Environmental Protection Agency's regulations under Subpart G of 40 
CFR 82, Protection of Stratospheric Ozone. Subpart G implements section 
612 of the Clean Air Act by determining safe alternatives to ozone-
depleting compounds. It is usually referred to as the ``Significant New 
Alternatives Policy'' (SNAP) program. The SNAP regulations take into 
consideration the toxicity of proposed substitutes for ozone-depleting 
compounds, but they also address potential impacts on atmospheric 
ozone, global warming and other issues related to human exposure and 
the environment. The FHWA is therefore proposing to require that fire 
extinguishers comply with the toxicity provisions of the SNAP 
regulations. While the other issues (ozone depletion, global warming, 
etc.) are important, there would be no practical reason to address 
these issues in Sec. 393.95.
Section 93.102--Securement Systems
    On July 6, 1994, the FHWA amended Sec. 393.102(b) to adopt the use 
of working load limits (WLL) in specifying the minimum strength of 
cargo securement devices (59 FR 34712). Under the new rule, the 
aggregate working load limit of the tiedown assemblies used to secure 
an article against movement in any direction must be at least \1/2\ 
times the weight of the article secured. Although the rule did not 
require manufacturers to attach a WLL label to their products, it did 
add a table of working load limits for unmarked webbing, wire rope, 
etc., to provide motor carriers with a means of determining the number 
of tiedown assemblies required.
    The FHWA did not provide guidance on unmarked welded steel chain, 
however. The National Association of Chain Manufacturers' (NACM) Welded 
Steel Chain Specifications (which were incorporated by reference into 
Sec. 393.102(b)) include guidelines on the marking of chain. While 
grades 43, 70, and 80 have periodic embossing for identification 
purposes, Grade 30, or proof coil chain, is marked at the option of the 
manufacturer. The use of unmarked chain for cargo securement purposes 
would not be a cause for concern if all unmarked chain were the same 
grade or strength. The FHWA has no indication that this is the case.
    Generally, manufacturers which meet the NACM's guidelines would 
mark their chain accordingly. But some manufacturers which produce 
chain that meets the NACM guidelines may choose, for whatever reason, 
not to mark their products. If unmarked chains of varying grades are 
readily available, motor carriers could unknowingly violate 
Sec. 393.102(b) by failing to have an adequate number of securement 
devices. The consequences for a load such as a steel or aluminum coil 
could be fatal to other motorists.
    The risks of such an accident could be greatly minimized by 
prohibiting motor carriers from using unmarked chain. Before doing so, 
the FHWA would have to quantify the potential economic burden on the 
motor carrier industry and those involved with the manufacture, sale, 
and distribution of unmarked chain. Since the FHWA has no reliable 
information on the number of manufacturers, distributors, and retailers 
of unmarked chain, the quality or strength of such chain, or the amount 
of this chain currently in use by motor carriers and in retailers'' 
stock, it would be inappropriate to propose a prohibition at this time. 
However, in view of the potential safety hazards of motor carriers 
misidentifying unmarked chain, the FHWA is proposing that all unmarked 
welded steel chain be considered to have a working load limit equal to 
that of grade 30 proof coil. This is consistent with the way in which 
the FHWA addressed the use of synthetic cordage (e.g., nylon, 
polypropylene, polyester) in the July 6, 1994, final rule. The FHWA 
specifically requests comments on this proposal.
Section 393.201--Frames
    In the final rule published on December 7, 1988 (53 FR 49380) 
prohibiting cracked, loose, sagging or broken frames, the FHWA 
inadvertently failed to include trailer frames. The FHWA proposes to 
remedy this oversight by replacing ``bus, truck and truck-tractor'' 
with the term ``commercial motor vehicles'' in paragraph (a).
    The FHWA is proposing to revise Sec. 393.201(d) to make the 
regulation more practical. Paragraph (d) was meant to prohibit welding 
on vehicle frames constructed of certain types of steel which would be 
weakened by the welding process. However, the current wording is overly 
restrictive. To address this issue, paragraph (d) would be revised to 
allow welding which is performed in accordance with the vehicle 
manufacturer's recommendations.
    In addition, the FHWA is proposing that paragraph (f) be removed. 
Paragraph (f) states that field repairs are allowed. There is no 
practical reason for retaining this provision since there was never a 
requirement that the motor carrier repair its vehicle only at certain 
locations.
Section 393.207--Suspension Systems
    The Truck Trailer Manufacturers Association (TTMA) petitioned the 
FHWA to amend part 393 to prohibit any device which is capable of 
dumping air individually from either of the two axle suspension systems 
on a semitrailer equipped with air-suspended ``spread'' or ``split'' 
tandem axles. The TTMA indicated that the petition was not intended to 
prohibit (1) devices that could exhaust air from both axle systems 
simultaneously or (2) lift axles on multi-axle units. The petition is 
available for review in the docket.
    According to the TTMA, about 30,000 semitrailers are manufactured 
each year with split tandem axles and air suspensions. These axles are 
not genuine tandems, but rather two single axles spaced at least 3,048 
mm (10 feet) apart, the minimum separation required by the bridge 
formula [23 U.S.C. 127(a)] before each of them can carry the full 9,072 
kg (20,000 pounds) allowed by Federal law. The TTMA estimates that 
5,000 of these trailers are also equipped with valves to depressurize 
the suspension system of one of the trailer axles, and sometimes of 
either axle. These valves are installed to compensate for problems 
created by the split tandem configuration. Normal tandems experience 
moderate tire scrubbing in turns because the trailer pivots around a 
point that lies between the two axles. Tire scrubbing is more severe in 
split tandems because the pivot point is much farther from either axle. 
Dumping air pressure from the suspension system of the rear (or less 
often the leading) trailer axle reduces its load and allows the trailer 
to pivot around the other axle with less resistance and tire scrubbing. 
The

[[Page 18186]]

TTMA's own tests showed that if each axle in a split tandem is loaded 
to 8,845 kg (19,500 pounds) and pressure in the rear axle is dumped, 
the resulting weight shift will make the front axle 3,175 to 5,443 kg 
(7,000 to 12,000 pounds) heavier than the rear.
    Dump valves were originally designed to aid maneuvering at 8 km/
hour (5 mph) or less, mainly at terminals or other loading points. 
According to the TTMA, however, many drivers now activate them at 
higher speeds on streets and highways to turn corners more easily and 
to reduce tire wear. The TTMA also believes that suspension pressure is 
sometimes vented accidentally because of wiring problems the moment the 
tractor hooks up to the trailer. In both cases, the inevitable weight 
shift often produces a load on the pressurized axle that exceeds the 
manufacturers' ratings for that axle and its wheels, tires and brakes. 
In addition, the loaded axle frequently exceeds the single-axle weight 
limit.
    The FHWA believes that the petition has merit and proposes to amend 
Sec. 393.207 to prohibit controls of this type. Although Sec. 393.3, 
which allows the use of equipment and accessories that do not decrease 
operational safety, could be interpreted as prohibiting the use of 
equipment to disable the air suspension of one axle on a two-axle 
trailer, addressing this issue through rulemaking is the most 
appropriate course of action.
Section 393.209--Steering Wheel Systems
    The FHWA is proposing to amend Sec. 393.209(b) to correct an error 
in the maximum steering wheel lash for 406 mm (16 inch) steering wheels 
and to add steering wheel lash limits for 483 mm (19 inch) and 533 mm 
(21 inch) diameter steering wheels. The table specifying steering wheel 
lash limits currently allows 114 mm (4\1/2\ inches) lash for steering 
wheel diameters of 406 mm (16 inches) or less if the vehicle has a 
power steering system. This corresponds to an angle of approximately 32 
degrees which is about 2 degrees more than the steering wheel lash 
limits for power steering systems using larger diameter steering 
wheels. Since there is no apparent technical basis for having a less 
stringent standard for 406 mm (16 inch) diameter steering wheel systems 
the FHWA proposes to change the steering wheel lash limit to 108 mm 
(4\1/4\ inches).
    The FHWA is proposing the addition of steering wheel lash limits 
for 483 mm (19 inch) and 533 mm (21 inch) diameter steering wheels 
because these are relatively common steering wheel sizes. The limits 
that would be adopted for these steering wheel diameters would be 
consistent with the 14 degree and 30 degree limits currently used for 
manual and power steering systems respectively.
    Section 393.209 would also be amended to include the term ball-and-
socket joints. Some steering system designs include ball-and-socket 
joints instead of universal joints. While the basic function of the two 
types of joints is similar, only universal joints are covered by 
Sec. 393.209(d). Defects or unsafe conditions of ball-and-socket joints 
are currently implicitly covered under Sec. 396.3(a)(1). The agency 
believes that such important items should be explicitly covered 
whenever possible.

Rulemaking Analyses and Notices

    All comments received before the close of business on the comment 
closing date indicated above will be considered and will be available 
for examination in the docket at the above address. Comments received 
after the comment closing date will be filed in the docket and will be 
considered to the extent practicable, but the FHWA may issue a final 
rule at any time after the close of the comment period. In addition to 
late comments, the FHWA will also continue to file in the docket 
relevant information that becomes available after the comment closing 
date, and interested persons should continue to examine the docket for 
new material.

Executive Order 12866 (Regulatory Planning and Review) and DOT 
Regulatory Policies and Procedures

    The FHWA has considered the impacts of this document and has 
determined that it is neither a significant rulemaking action within 
the meaning of Executive Order 12866 nor a significant rulemaking under 
the regulatory policies and procedures of the Department of 
Transportation. The rulemaking would amend parts 390, 392, and 393 of 
the FMCSRs by removing obsolete and redundant regulatory language; 
responding to several petitions for rulemaking; providing improved 
definitions of vehicle types, systems, and components; resolving 
inconsistencies between part 393 and the FHWA's periodic inspection 
criteria (appendix G to subchapter B); resolving inconsistencies 
between part 393 and the NHTSA's Federal Motor Vehicle Safety Standards 
(49 CFR 571); and codifying certain FHWA regulatory guidance concerning 
the requirements of part 393. Generally, the proposed amendments do not 
involve the establishment of new or more stringent requirements but a 
clarification of existing requirements. It is anticipated that the 
economic impact of this rulemaking will be minimal. Therefore, a full 
regulatory evaluation is not required.
    The new or more stringent requirements include a cross-reference to 
the NHTSA's compressed natural gas (CNG) fuel container regulations 
which would result in carriers having to ensure that the CNG containers 
are properly maintained. In addition, the agency is proposing to 
prohibit certain controls used for dumping air individually from either 
of the two-axle suspension systems on a semitrailer equipped with air-
suspended ``spread'' or ``split'' tandem axles. The FHWA does not 
believe the new requirements will result in an increased economic 
burden on the motor carrier industry.

Regulatory Flexibility Act

    In compliance with the Regulatory Flexibility Act (5 U.S.C. 601-
612), the FHWA has evaluated the effects of this rule on small 
entities. Based on this evaluation, and for the reasons set forth in 
the preceeding paragraph, the FHWA certifies that this rule would not 
have a significant economic impact on a substantial number of small 
entities.

Executive Order 12612 (Federalism Assessment)

    This action has been analyzed in accordance with the principles and 
criteria contained in Executive Order 12612, and it has been determined 
that this rule does not have sufficient federalism implications to 
warrant the preparation of a Federalism Assessment.

Executive Order 12372 (Intergovernmental Review)

    Catalog of Domestic Assistance Program Number 20.217, Motor Carrier 
Safety. The regulations implementing Executive Order 12372 regarding 
intergovernmental consultation on Federal programs and activities do 
not apply to this program.

Paperwork Reduction Act

    This document does not contain information collection requirements 
for the purposes of the Paperwork Reduction Act of 1980 [44 U.S.C. 3501 
et seq.].

National Environmental Policy Act

    The agency has analyzed this rulemaking for the purpose of the 
National Environmental Policy Act of 1969 (42 U.S.C. 4321 et seq.) and 
has determined that this action would not have any effect on the 
quality of the environment.

[[Page 18187]]

Regulation Identification Number

    A regulation identification number (RIN) is assigned to each 
regulatory action listed in the Unified Agenda of Federal Regulations. 
The Regulatory Information Service Center publishes the Unified Agenda 
in April and October of each year. The RIN contained in the heading of 
this document can be used to cross-reference this action with the 
Unified Agenda.

List of Subjects in 49 CFR Part 390

    Highway safety, Highways and roads, Intermodal transportation, 
Motor carriers, Motor vehicle identification, Motor vehicle safety, 
Reporting and recordkeeping requirements.

49 CFR Part 392

    Highway safety, Highways and roads, Motor carriers--driving 
practices, Motor vehicle safety.

49 CFR Part 393

    Highways and roads, Incorporation by reference, Motor carriers, 
Motor vehicle equipment, Motor vehicle safety.

    Issued on: April 1, 1997.
Jane Garvey,
Acting Administrator, Federal Highway Administration.

    In consideration of the foregoing, the FHWA proposes to amend title 
49, Code of Federal Regulations, subchapter B, chapter III, as follows:

PART 390--[AMENDED]

    1. The authority citation for Part 390 continues to read as 
follows:

    Authority: 49 U.S.C. 5901-5907, 13301, 13902, 31132, 31133, 
31136, 31502, and 31504; 49 CFR 1.48.

    2. Section 390.5 is amended by revising the definition of 
driveaway-towaway operation to read as follows:


Sec. 390.5  Definitions.

* * * * *
    Driveaway-towaway operation means an operation in which an empty or 
unladen motor vehicle with one or more set of wheels on the surface of 
the roadway is being transported
    (1) between a vehicle manufacturer and a dealership or purchaser,
    (2) between a dealership or other entity selling or leasing the 
vehicle and a purchaser or lessee,
    (3) to a maintenance/repair facility for the repair of disabling 
damage (as defined in Sec. 390.5), or
    (4) by means of a saddle-mount.
* * * * *

PART 392--[AMENDED]

    3. The authority citation for Part 392 is revised to read as 
follows:

    Authority: Section 1041(b) of Pub. L. 102-240, 105 Stat. 1914, 
1993 (1991), 49 U.S.C. 31136 and 31502; 49 CFR 1.48.

    4. Section 392.33 is revised to read as follows:


Sec. 392.33  Obscured lamps or reflective devices/material.

    (a) No commercial motor vehicle shall be driven when any of the 
lamps or reflective devices/material required by subpart B of part 393 
are obscured by the tailboard, or by any part of the load, by dirt, or 
otherwise.
    (b) Exception. The conspicuity treatments on the front end 
protection devices of the trailer may be obscured by part of the load 
being transported.

PART 393--[AMENDED]

    5. The authority citation for part 393 continues to read as 
follows:

    Authority: Section 1041(b) of Pub. L. 102-240, 105 Stat. 1914, 
1993 (1991); 49 U.S.C. 31136 and 31502; 49 CFR 1.48.

    6. Section 393.1 is revised to read as follows:


Sec. 393.1  Scope of the rules in this part.

    (a) The rules in this part establish minimum standards for 
commercial motor vehicles as defined in Sec. 390.5 of this title. Only 
motor vehicles (as defined in Sec. 390.5) and combinations of motor 
vehicles which meet the definition of a commercial motor vehicle are 
subject to the requirements of this part. All requirements that refer 
to motor vehicles with a GVWR below 4,536 kg (10,001 pounds) are 
applicable only when the motor vehicle or combination of motor vehicles 
meets the definition of a commercial motor vehicle.
    (b) Every employer and employee shall comply and be conversant with 
the requirements and specifications of this part. No employer shall 
operate a commercial motor vehicle, or cause or permit it to be 
operated, unless it is equipped in accordance with the requirements and 
specifications of this part.
    7. Section 393.5 is amended by removing the definition of ``bus''; 
and by adding definitions for ``air brake system,'' ``air-over-
hydraulic brake system,'' ``auxiliary driving lamp,'' ``boat trailer,'' 
``brake power assist unit,'' ``brake power unit,'' ``container chassis 
trailer,'' ``electric brake system,'' ``emergency brake,'' ``front fog 
lamp,'' ``hydraulic brake system,'' ``intermodal shipping container,'' 
``multi-piece windshield,'' ``split service brake system,'' ``tow 
bar,'' ``trailer kingpin,'' ``vacuum brake system,'' ``windshield''; 
and by revising the definitions of ``chassis,'' ``clearance lamp,'' 
``container chassis'' (now ``container chassis trailer''), ``heater,'' 
``heavy hauler trailer,'' ``parking brake system,'' ``side marker lamp 
(intermediate),'' and ``side marker lamps'', keeping them in 
alphabetical order, to read as follows:


Sec. 393.5  Definitions.

* * * * *
    Air brake system. A system, including an air-over-hydraulic brake 
subsystem, that uses air as a medium for transmitting pressure or force 
from the driver control to the service brake, but does not include a 
system that uses compressed air or vacuum only to assist the driver in 
applying muscular force to hydraulic or mechanical components.
    Air-over-hydraulic brake subsystem. A subsystem of the air brake 
system that uses compressed air to transmit a force from the driver 
control to a hydraulic brake system to actuate the service brakes.
    Auxiliary driving lamp. A lighting device mounted to provide 
illumination forward of the vehicle which supplements the upper beam of 
a standard headlamp system. It is not intended for use alone or with 
the lower beam of a standard headlamp system.
    Boat trailer. A trailer designed with cradle-type mountings to 
transport a boat and configured to permit launching of the boat from 
the rear of the trailer.
* * * * *
    Brake power assist unit. A device installed in a hydraulic brake 
system that reduces the operator effort required to actuate the system, 
but which if inoperative does not prevent the operator from braking the 
vehicle by a continued application of muscular force on the service 
brake control.
    Brake power unit. A device installed in a brake system that 
provides the energy required to actuate the brakes, either directly or 
indirectly through an auxiliary device, with the operator action 
consisting only of modulating the energy application level.
* * * * *
    Chassis. The load-supporting frame of a commercial motor vehicle, 
exclusive of any appurtenances which might be added to accommodate 
cargo.
    Clearance Lamps. Lamps mounted on the permanent structure of the 
vehicle as near as practicable to the upper left and right extreme 
edges that provide light to the front or rear to indicate the overall 
width and height of the vehicle.
    Container chassis trailer. A semitrailer of skeleton construction

[[Page 18188]]

limited to a bottom frame, one or more axles, specially built and 
fitted with locking devices for the transport of intermodal cargo 
containers, so that when the chassis and container are assembled, the 
units serve the same function as an over the road trailer.
* * * * *
    Electric brake system. A system that uses electric current to 
actuate the service brake.
    Emergency brake. A mechanism designed to stop a motor vehicle after 
a failure of the service brake system.
* * * * *
    Front fog lamp. A lighting device mounted to provide illumination 
forward of the vehicle under conditions of rain, snow, dust, or fog. 
The lamp may be used with a lower beam headlamp or switch controlled in 
conjunction with the headlamps and used at the driver's discretion with 
either low or high beam headlamps.
* * * * *
    Heater. Any device or assembly of devices or appliances used to 
heat the interior of any motor vehicle. This includes a catalytic 
heater which must meet the requirements of Sec. 177.834(l)(2) of this 
title when Class 3 (flammable liquid) or Division 2.1 (flammable gas) 
is transported.
    Heavy hauler trailer. A trailer which has one or more of the 
following characteristics, but which is not a container chassis 
trailer:
    (1) Its brake lines are designed to adapt to separation or 
extension of the vehicle frame; or
    (2) Its body consists only of a platform whose primary cargo-
carrying surface is not more than 1,016 mm (40 inches) above the ground 
in an unloaded condition, except that it may include sides that are 
designed to be easily removable and a permanent ``front-end structure'' 
as that term is used in Sec. 393.106 of this title.
* * * * *
    Hydraulic brake system. A system that uses hydraulic fluid as a 
medium for transmitting force from a service brake control to the 
service brake, and that may incorporate a brake power assist unit, or a 
brake power unit.
* * * * *
    Intermodal shipping container. An article of transport equipment;
    (1) Of a permanent character and accordingly strong enough to be 
suitable for repeated use;
    (2) Specially designed to facilitate the carriage of goods by one 
or more modes of transport, without intermediate reloading;
    (3) Fitted with devices permitting its ready handling, particularly 
its transfer from one mode of transport to another;
    (4) So designed as to be easy to fill and empty; and
    (5) Having an internal volume of one cubic meter (35.3 cubic feet) 
or more.
* * * * *
    Multi-piece windshield. A windshield consisting of two or more 
windshield glazing surface areas.
    Parking brake system. A mechanism designed to prevent the movement 
of a stationary motor vehicle.
* * * * *
    Side marker lamp (Intermediate). A lamp shown to the side of a 
motor vehicle to indicate the approximate middle of the vehicle, when 
the motor vehicle is 9.14 meters (30 feet) or more in length.
    Side marker lamps. Lamps mounted on the permanent structure of the 
motor vehicle as near as practicable to the front and rear edges, that 
provide light to the side to indicate the overall length of the motor 
vehicle.
    Split service brake system. A brake system consisting of two or 
more subsystems actuated by a single control designed so that a 
leakage-type failure of a pressure component in a single subsystem 
(except structural failure of a housing that is common to two or more 
subsystems) shall not impair the operation of any other subsystem.
* * * * *
    Tow bar. A strut or column-like device temporarily attached between 
the rear of a towing vehicle and the front of the vehicle being towed.
    Trailer kingpin. A pin (with a flange on its lower end) which 
extends vertically from the front of the underside of a semitrailer and 
which locks into a fifth wheel.
* * * * *
    Vacuum brake system. A system that uses a vacuum and atmospheric 
pressure for transmitting a force from the driver control to the 
service brake, not including a system that uses vacuum only to assist 
the driver in applying muscular force to hydraulic or mechanical 
components.
    Windshield. The principal forward facing glazed surface provided 
for forward vision in operating a motor vehicle.
    8. Section 393.7 is amended by adding paragraphs (b)(7) and (b)(8) 
to read as follows:


Sec. 393.7  Matter incorporated by reference.

* * * * *
    (b) * * *
    (7) Standards of the Society of Automotive Engineers (SAE). 
Information and copies may be obtained by writing to: Society of 
Automotive Engineers, Inc., 400 Commonwealth Drive, Warrendale, 
Pennsylvania 15096.
    (8) Standards of the American National Standards Institute (ANSI). 
Information and copies may be obtained by writing to: American National 
Standards Institute, 11 West 42nd Street, New York, New York 10036.
* * * * *
    9. The title of subpart B is revised to read as follows:

Subpart B--Lamps, Reflective Devices, and Electrical Wiring

    10. Section 393.9 is revised to read as follows:


Sec. 393.9  Lamps operable, prohibition of obstructions of lamps and 
reflectors.

    (a) All lamps required by this subpart shall be capable of being 
operated at all times. This paragraph shall not be construed to require 
that any auxiliary or additional lamp be capable of operating at all 
times.
    (b) Lamps and reflective devices/material required by this subpart 
must not be obscured by the tailboard, or by any part of the load, by 
dirt, or otherwise. Exception: The conspicuity treatments on the front 
end protection devices may be obscured by part of the load being 
transported.
    11. Section 393.11 is amended by revising paragraphs (a) through 
(c), table 1 and footnotes 4 through 10 and 15, and adding footnotes 16 
and 17 to read as follows:


Sec. 393.11  Lamps and reflective devices.

    (a)(1) Lamps and reflex reflectors. Table 1 of this section 
specifies the requirements for lamps, reflective devices and associated 
equipment by the type of commercial motor vehicle. The diagrams in this 
section illustrate the position of the lamps, reflective devices and 
associated equipment specified in Table 1. All commercial motor 
vehicles manufactured on or after December 25, 1968, must, at a 
minimum, meet the applicable requirements of 49 CFR 571.108 (FMVSS No. 
108) in effect at the time of manufacture of the vehicle. Commercial 
motor vehicles manufactured before December 25, 1968, must, at a 
minimum, meet the requirements of this subpart in effect at the time of 
manufacture.
    (2) Exceptions: Pole trailers and trailer converter dollies must 
meet the part 393 requirements for lamps, reflective devices and 
electrical equipment in effect at the time of manufacture. Trailers 
which are equipped with conspicuity material which meets the

[[Page 18189]]

requirements of paragraph (b) of this section are not required to be 
equipped with the reflex reflectors listed in Table 1 if--
    (i) The conspicuity material is placed at the locations where 
reflex reflectors are required by Table 1; and
    (ii) The conspicuity material when installed on the motor vehicle 
meets the geometric visibility requirements for the reflex reflectors.
    (b) Conspicuity systems. Each trailer of 2,032 mm (80 inches) or 
more overall width, and with a GVWR over 4,536 kg (10,000 pounds), 
manufactured on or after December 1, 1993, except pole trailers and 
trailers designed exclusively for living or office use, shall be 
equipped with either retroreflective sheeting that meets the 
requirements of FMVSS No. 108 (49 CFR 571.108, S5.7.1), reflex 
reflectors that meet the requirements FMVSS No. 108 (49 CFR 571.108, 
S5.7.2), or a combination of retroreflective sheeting and reflex 
reflectors that meet the requirements of FMVSS No. 108 (49 CFR 571.108, 
S5.7.3). The conspicuity system shall be installed and located as 
specified in FMVSS No. 108 (49 CFR 571.108) [S5.7.1.4 (for 
retroreflective sheeting), S5.7.2.2 (for reflex reflectors), S5.7.3 
(for a combination of sheeting and reflectors)] and have certification 
and markings as required by S5.7.1.5 (for retroreflective tape) and 
S5.7.2.3 (for reflex reflectors).
    (c) Prohibition on the use of amber stop lamps and tail lamps. No 
commercial motor vehicle may be equipped with an amber stop lamp, tail 
lamp, or other lamp which is optically combined with an amber stop lamp 
or tail lamp.

                                          Table 1.--Required Lamps and Reflectors on Commercial Motor Vehicles                                          
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                        Height above                                    
                                                                                                          the road                                      
                                                                                                         surface in                                     
                                                                                                        millimeters                                     
                                                                                                         (mm) (with                                     
     Item on the vehicle         Quantity         Color            Location           Position         English units     Vehicles for which the devices 
                                                                                                      in parenthesis)             are required          
                                                                                                       measured from                                    
                                                                                                       the center of                                    
                                                                                                        the lamp at                                     
                                                                                                        curb weight                                     
--------------------------------------------------------------------------------------------------------------------------------------------------------
Headlamps....................            2  White............  Front..........  On the front at the   Not less than    A, B, C                          
                                                                                 same height, with     559 mm (22                                       
                                                                                 an equal number at    inches) nor                                      
                                                                                 each side of the      more than                                        
                                                                                 vertical centerline   1,372 mm (54                                     
                                                                                 as far apart as       inches).                                         
                                                                                 practicable.                                                           
Turn signal (front). See                 2  Amber............  At or near the   One on each side of   Not less than    A, B, C                          
 footnotes #2 and 12.                                           front.           the vertical          381 mm (15                                       
                                                                                 centerline at the     inches) nor                                      
                                                                                 same height and as    more than                                        
                                                                                 far apart as          2,108 mm (83                                     
                                                                                 practicable.          inches).                                         
Identification lamps (front).            3  Amber............  Front..........  As close as           All three on     B, C                             
 See footnote #1.                                                                practicable to the    the same level                                   
                                                                                 top of the vehicle,   as close as                                      
                                                                                 at the same height,   practicable to                                   
                                                                                 and as close as       the top of the                                   
                                                                                 practicable to the    motor vehicle.                                   
                                                                                 vertical centerline                                                    
                                                                                 of the vehicle (or                                                     
                                                                                 the vertical                                                           
                                                                                 centerline of the                                                      
                                                                                 cab where different                                                    
                                                                                 from the centerline                                                    
                                                                                 of the vehicle)                                                        
                                                                                 with lamp centers                                                      
                                                                                 spaced not less                                                        
                                                                                 than 152 mm (6                                                         
                                                                                 inches) or more                                                        
                                                                                 than 305 mm (12                                                        
                                                                                 inches) apart.                                                         
                                                                                Alternatively, the                                                      
                                                                                 front lamps may be                                                     
                                                                                 located as close as                                                    
                                                                                 practicable to the                                                     
                                                                                 top of the cab.                                                        
Tail lamps. See footnotes #5             2  Red..............  Rear...........  One lamp on each      Both on the      A, B, C, D, E, F, G, H           
 and 11.                                                                         side of the           same level                                       
                                                                                 vertical centerline   between 381 mm                                   
                                                                                 at the same height    (15 inches)                                      
                                                                                 and as far apart as   and 1,829 mm                                     
                                                                                 practicable.          (72 inches).                                     
Stop lamps. See footnotes #5             2  Red..............  Rear...........  One lamp on each      Both on the      A, B, C, D, E, F, G              
 and 13.                                                                         side of the           same level                                       
                                                                                 vertical centerline   between 381 mm                                   
                                                                                 at the same height    (15 inches)                                      
                                                                                 and as far apart as   and 1,829 mm                                     
                                                                                 practicable.          (72 inches).                                     

[[Page 18190]]

                                                                                                                                                        
Clearance lamps. See                     2  Amber............  One on each      One on each side of   Both on the      B, C, D, G, H                    
 footnotes #8, 9, 10, 15 & 17.                                  side of the      the vertical          same level as                                    
                                                                rear of the      centerline to         high as                                          
                                                                vehicle.         indicate overall      practicable.                                     
                                                                                 width.                                                                 
                                         2  Red..............  One on each      One on each side of   Both on the      B, D, G, H                       
                                                                side of the      the vertical          same level as                                    
                                                                front of the     centerline to         high as                                          
                                                                vehicle.         indicate overall      practicable.                                     
                                                                                 width.                                                                 
Reflex reflector,                        2  Amber............  One on each      At or near the        Between 381 mm   A, B, D, F, G                    
 intermediate (side).                                           side.            midpoint between      (15 inches)                                      
                                                                                 the front and rear    and 1,524 mm                                     
                                                                                 side marker lamps,    (60 inches).                                     
                                                                                 if the length of                                                       
                                                                                 the vehicle is more                                                    
                                                                                 than 9,144 mm (30                                                      
                                                                                 feet).                                                                 
Reflex reflector (rear). See             2  Red..............  Rear...........  One on each side of   Both on the      A, B, C, D, E, F, G              
 footnotes #5, 6, and 8.                                                         the vertical          same level,                                      
                                                                                 centerline, as far    between 381 mm                                   
                                                                                 apart as              (15 inches)                                      
                                                                                 practicable and at    and 1,524 mm                                     
                                                                                 the same height.      (60 inches).                                     
Reflex reflector (rear side).            2  Red..............  One on each      As far to the rear    Both on the      A, B, D, F, G                    
                                                                side (rear).     as practicable.       same level,                                      
                                                                                                       between 381 mm                                   
                                                                                                       (15 inches)                                      
                                                                                                       and 1,524 mm                                     
                                                                                                       (60 inches).                                     
Reflex reflector (front                  2  Amber............  One on each      As far to the front   Between 381 mm   A, B, C, D, F, G                 
 side). See footnote #16.                                       side (front).    as practicable.       (15 inches)                                      
                                                                                                       and 1,524 mm                                     
                                                                                                       (60 inches).                                     
License plate lamp (rear).               1  White............  At rear license                        No requirements  A, B, C, D, F, G                 
 See footnote #11.                                              plate to                                                                                
                                                                illuminate the                                                                          
                                                                plate from the                                                                          
                                                                top or sides.                                                                           
Side marker lamp (front). See            2  Amber............  One on each      As far to the front   Not less than    A, B, C, D, F                    
 footnote #16.                                                  side.            as practicable.       381 mm (15                                       
                                                                                                       inches).                                         
Side marker lamp,                        2  Amber............  One on each      At or near the        Not less than    A, B, D, F, G                    
 intermediate.                                                  side.            midpoint between      381 mm (15                                       
                                                                                 the front and rear    inches).                                         
                                                                                 side marker lamps,                                                     
                                                                                 if the length of                                                       
                                                                                 the vehicle is more                                                    
                                                                                 than 9,144 mm (30                                                      
                                                                                 feet).                                                                 
Side marker lamp (rear). See             2  Red..............  One on each      As far to the rear    Not less than    A, B, D, F, G                    
 footnotes #4 and 8.                                            side.            as practicable.       381 mm (15                                       
                                                                                                       inches) and,                                     
                                                                                                       on the rear of                                   
                                                                                                       trailers, not                                    
                                                                                                       more than                                        
                                                                                                       1,524 mm (60                                     
                                                                                                       inches).                                         

[[Page 18191]]

                                                                                                                                                        
Turn signal (rear). See                  2  Amber or red.....  Rear...........  One lamp on each      Both on the      A, B, C, D, E, F, G              
 footnotes #5 and 12.                                                            side of the           same level,                                      
                                                                                 vertical centerline   between 381 mm                                   
                                                                                 as far apart as       (15 inches)                                      
                                                                                 practicable.          and 2,108 mm                                     
                                                                                                       (83 inches).                                     
Identification lamp (rear).              3  Red..............  Rear...........  One as close as       All three on     B, D, G                          
 See footnotes #3, 7, and 15.                                                    practicable to the    the same level                                   
                                                                                 vertical              as close as                                      
                                                                                 centerline. One on    practicable to                                   
                                                                                 each side with lamp   the top of the                                   
                                                                                 centers spaced not    vehicle.                                         
                                                                                 less than 152 mm (6                                                    
                                                                                 inches) or more                                                        
                                                                                 than 305 mm (12                                                        
                                                                                 inches) apart.                                                         
Vehicular hazard warning                 2  Amber............  Front..........  One lamp on each      Both on the      A, B, C,                         
 signal flasher lamps. See                                                       side of the           same level,                                      
 footnotes #5 and 12.                                                            vertical              between 381 mm                                   
                                                                                 centerline, as far    (15 inches)                                      
                                                                                 apart as              and 2,108 mm                                     
                                                                                 practicable.          (83 inches).                                     
                                         2  Amber or red.....  Rear...........  One lamp on each      Both on the      A, B, C, D, E, F, G              
                                                                                 side of the           same level,                                      
                                                                                 vertical              between 381 mm                                   
                                                                                 centerline, as far    (15 inches)                                      
                                                                                 apart as              and 2,108 mm                                     
                                                                                 practicable.          (83 inches).                                     
Backup lamp. See footnote #14            1  White............  Rear...........  Rear................  No requirement.  A, B, C                          
Parking lamp.................            2  Amber or white...  Front..........  One lamp on each      Both on the      A                                
                                                                                 side of the           same level,                                      
                                                                                 vertical              between 381 mm                                   
                                                                                 centerline, as far    (15 inches)                                      
                                                                                 apart as              and 1,829 mm                                     
                                                                                 practicable.          (72 inches).                                     
--------------------------------------------------------------------------------------------------------------------------------------------------------
Legend: Types of commercial motor vehicles shown in the last column of Table 1.                                                                         
A. Buses and trucks less than 2,032 mm (80 inches) in overall width.                                                                                    
B. Buses and trucks 2,032 mm (80 inches) or more in overall width.                                                                                      
C. Truck tractors.                                                                                                                                      
D. Semitrailers and full trailers 2,032 mm (80 inches) or more in overall width except converter dollies.                                               
E. Converter dolly.                                                                                                                                     
F. Semitrailers and full trailers less than 2,032 mm (80 inches) in overall width.                                                                      
G. Pole trailers.                                                                                                                                       
H. Projecting loads.                                                                                                                                    
Note: Lamps and reflectors may be combined as permitted by Sec.  393.22 and S5.4 of 49 CFR 571.108, Equipment combinations.                             

* * * * *

Footnote--4

    Any semitrailer or full trailer manufactured on or after March 1, 
1979, shall be equipped with rear side-marker lamps at a height of not 
less than 381 mm (15 inches) nor more than 1,524 mm (60 inches) above 
the road surface, as measured from the center of the lamp on the 
vehicle at curb weight.

Footnote--5

    Each converter dolly, when towed singly by another vehicle and not 
as part of a full trailer, shall be equipped with one stop lamp, one 
tail lamp, and two reflectors (one on each side of the vertical 
centerline, as far apart as practicable) on the rear. Each converter 
dolly shall be equipped with rear turn signals and vehicular hazard 
warning signal flasher lamps when towed singly by another vehicle and 
not as part of a full trailer, if the converter dolly obscures the turn 
signals at the rear of the towing vehicle.

Footnote--6

    Pole trailers shall be equipped with two reflex reflectors on the 
rear, one on each side of the vertical centerline as far apart as 
practicable, to indicate the extreme width of the trailer.

[[Page 18192]]

Footnote--7

    Pole trailers, when towed by motor vehicles with rear 
identification lamps meeting the requirements of Sec. 393.11 and 
mounted at a height greater than the load being transported on the pole 
trailer, are not required to have rear identification lamps.

Footnote--8

    Pole trailers shall have on the rearmost support for the load: (1) 
Two front clearance lamps, one on each side of the vehicle, both on the 
same level and as high as practicable to indicate the overall width of 
the pole trailer; (2) two rear clearance lamps, one on each side of the 
vehicle, both on the same level and as high as practicable to indicate 
the overall width of the pole trailer; (3) two rear side marker lamps, 
one on each side of the vehicle, both on the same level, not less than 
375 mm (15 inches) above the road surface; (4) two rear reflex 
reflectors, one on each side, both on the same level, not less than 375 
mm (15 inches) above the road surface to indicate maximum width of the 
pole trailer; and (5) one red reflector on each side of the rearmost 
support for the load. Lamps and reflectors may be combined as allowed 
in Sec. 393.22.

Footnote--9

    Any motor vehicle transporting a load which extends more than 102 
mm (4 inches) beyond the overall width of the motor vehicle shall be 
equipped with the following lamps in addition to other required lamps 
when operated during the hours when headlamps are required to be used.
    (1) The foremost edge of that portion of the load which projects 
beyond the side of the vehicle shall be marked (at its outermost 
extremity) with an amber lamp visible from the front and side.
    (2) The rearmost edge of that portion of the load which projects 
beyond the side of the vehicle shall be marked (at its outermost 
extremity) with a red lamp visible from the rear and side.
    (3) If the projecting load does not measure more than 914 mm (3 
feet) from front to rear, it shall be marked with an amber lamp visible 
from the front, both sides, and rear, except that if the projection is 
located at or near the rear it shall be marked by a red lamp visible 
from front, side, and rear.

Footnote--10

    Projections beyond rear of motor vehicles. Motor vehicles 
transporting loads which extend more than 1,219 mm (4 feet) beyond the 
rear of the motor vehicle, or which have tailboards or tailgates 
extending more than 1,219 mm (4 feet) beyond the body, shall have these 
projections marked as follows when the vehicle is operated during the 
hours when headlamps are required to be used:
    (1) On each side of the projecting load, one red side marker lamp, 
visible from the side, located so as to indicate maximum overhang.
    (2) On the rear of the projecting load, two red lamps, visible from 
the rear, one at each side; and two red reflectors visible from the 
rear, one at each side, located so as to indicate maximum width.
* * * * *

Footnote--15

    (1) For the purposes of Sec. 393.11, the term ``overall width'' 
refers to the nominal design dimension of the widest part of the 
vehicle, exclusive of the signal lamps, marker lamps, outside rearview 
mirrors, flexible fender extensions, and mud flaps.
    (2) Clearance lamps may be mounted at a location other than on the 
front and rear if necessary to indicate the overall width of a vehicle, 
or for protection from damage during normal operation of the vehicle.
    (3) On a trailer, the front clearance lamps may be mounted at a 
height below the extreme height if mounting at the extreme height 
results in the lamps failing to mark the overall width of the trailer.
    (4) On a truck tractor, clearance lamps mounted on the cab may be 
located to indicate the width of the cab, rather than the width of the 
vehicle.
    (5) When the rear identification lamps are mounted at the extreme 
height of a vehicle, rear clearance lamps are not required to be 
located as close as practicable to the top of the vehicle.

Footnote--16

    A trailer subject to this part that is less than 1829 mm (6 feet) 
in overall length, including the trailer tongue, need not be equipped 
with front side marker lamps and front side reflex reflectors.

Footnote--17

    A boat trailer subject to this part whose overall width is 2032 mm 
(80 inches) or more need not be equipped with both front and rear 
clearance lamps provided an amber (front) and red (rear) clearance lamp 
is located at or near the midpoint on each side so as to indicate its 
extreme width.
* * * * *
    12. Section 393.17 is amended by revising the text below the 
illustrations to the tow-bar diagram, the double-saddle-mount diagram 
and the single-saddle-mount diagram to read as follows:


Sec. 393.17  Lamps and reflectors--combinations in driveaway-towaway 
operation.

* * * * *
(Tow-bar diagram to illustrate Sec. 393.17.)
* * * * *
    Lamps may be combined as permitted by Sec. 393.22. The color of 
exterior lighting devices and reflectors shall conform to requirements 
of Sec. 393.11.
* * * * *
(Double-saddle-mount diagram to illustrate Sec. 393.17.)
* * * * *
    Lamps may be combined as permitted by Sec. 393.22. The color of 
exterior lighting devices and reflectors shall conform to the 
requirements of Sec. 393.11.
* * * * *
(Single-saddle-mount diagram to illustrate Sec. 393.17.)
* * * * *
    Lamps may be combined as permitted by Sec. 393.22. The color of 
exterior lighting devices and reflectors shall conform to requirements 
of Sec. 393.11.
    13. Section 393.19 is revised to read as follows:


Sec. 393.19  Hazard warning signals.

    The hazard warning signal operating unit on each commercial motor 
vehicle shall operate independently of the ignition or equivalent 
switch, and when activated, cause all turn signals required by 
Sec. 393.11 to flash simultaneously.


Sec. 393.20   [Removed and Reserved]

    14. Section 393.20 is removed and reserved.
    15. Section 393.23 is revised to read as follows:


Sec. 393.23  Power supply for lamps.

    All required lamps must be powered by the electrical system of the 
motor vehicle with the exception of battery powered lamps used on 
projecting loads.
    16. Section 393.24 is revised to read as follows:


Sec. 393.24  Requirements for head lamps, auxiliary driving lamps and 
front fog lamps.

    (a) Headlamps. Every bus, truck and truck tractor shall be equipped 
with headlamps as required by Sec. 393.11(a). The headlamps shall 
provide an upper and lower distribution of light, selectable at the 
driver's will and be steady-burning. The headlamps shall be marked in 
accordance with FMVSS No. 108, 49 CFR 571.108, S7.2. Auxiliary driving 
lamps and/or front fog lamps may not be used to satisfy the 
requirements of this paragraph.
    (b) Auxiliary driving lamps and front fog lamps. Commercial motor 
vehicles may be equipped with auxiliary driving lamps and/or front fog 
lamps for use in conjunction with, but not in lieu of the required 
headlamps. Auxiliary driving lamps shall meet SAE Standard J581 
Auxiliary Driving Lamps, January 1995, and front fog lamps shall meet 
SAE

[[Page 18193]]

Standard J583 Front Fog Lamps, June 1993. (See Sec. 393.7(b) for 
information on the incorporation by reference and availability of this 
document.)
    (c) Mounting. Headlamps, auxiliary driving lamps and front fog 
lamps shall be mounted so that the beams are adjustable, both 
vertically and horizontally and the mounting shall prevent the aim of 
the lighting device from being disturbed while the vehicle is operating 
on public roads.
    (d) Aiming and intensity. Headlamps shall be constructed and 
installed to meet, at a minimum, the applicable requirements of FMVSS 
No. 108 in effect at the time the vehicle was manufactured. Auxiliary 
driving lamps and front fog lamps shall meet the aiming and intensity 
specifications in the SAE standards referenced in paragraph (b) of this 
section.
    17. Section 393.25 is revised to read as follows:


Sec. 393.25  Requirements for lamps other than head lamps.

    (a) Mounting. All lamps shall be securely mounted on a rigid part 
of the vehicle. Temporary lamps must be securely mounted to the load 
and are not required to be mounted to a permanent part of the vehicle.
    (b) Visibility. Each lamp shall be located so that it meets the 
visibility requirements specified by FMVSS No. 108 in effect at the 
time of manufacture of the vehicle. Vehicles which were not subject to 
FMVSS No. 108 at the time of manufacture shall have each lamp located 
so that is meets the visibility requirements specified in the SAE 
standards listed in paragraph (c) of this section. If motor vehicle 
equipment (e.g., mirrors, snow plows, wrecker booms, backhoes, and 
winches) prevents compliance with this paragraph by any required lamp, 
an auxiliary lamp or device meeting the requirements of this paragraph 
shall be provided. This shall not be construed to apply to lamps on one 
unit which are obscured by another unit of a combination of vehicles.
    (c) Specifications. All required lamps (except marker lamps on 
projecting loads, lamps which are temporarily attached to vehicles 
transported in driveaway-towaway operations, and lamps on converter 
dollies and pole trailers) on vehicles manufactured on or after 
December 25, 1968, shall, at a minimum, meet the applicable 
requirements of FMVSS No. 108 in effect on the date of manufacture of 
the vehicle. Marker lamps on projecting loads, all lamps which are 
temporarily attached to vehicles transported in driveaway-towaway 
operations, and all lamps on converter dollies and pole trailers must 
meet the following applicable SAE standards: J586--Stop Lamps for Use 
on Motor Vehicles Less Than 2032 mm in Overall Width, December 1989; 
J1398--Stop Lamps for Use on Motor Vehicles 2032 mm or More in Overall 
Width, May 1985; J585--Tail Lamps (Rear Position Lamps) for Use on 
Motor Vehicles Less Than 2032 mm in Overall Width, December 1994; 
J588--Turn Signal Lamps for Use on Motor Vehicles Less J2040--Tail 
Lamps (Rear Position Lamps) for Use on Motor Vehicles 2032 mm or More 
in Overall Width, June 1991; J588--Turn Signal Lamps for Use on Motor 
Vehicles Less Than 2032 mm in Overall Width, December 1994; J1395--
Front and Rear Turn Signal Lamps for Use on Motor Vehicles 2032 mm or 
More Overall Width, June 1991; J592--Clearance, Side Marker, and 
Identification Lamps, December 1994. (See Sec. 393.7(b) for information 
on the incorporation by reference and availability of these documents.)
    (d) (Reserved).
    (e) Lamps to be steady-burning. All exterior lamps (both required 
lamps and any additional lamps) shall be steady-burning with the 
exception of turn signal lamps; hazard warning signal lamps; school bus 
warning lamps; amber Class 2 or Class 3, 360 degree warning lamps or 
flashing warning lamps on tow trucks and commercial motor vehicles 
transporting oversized loads; and warning lamps on emergency and 
service vehicles authorized by State or local authorities. Lamps 
combined into the same shell or housing with a turn signal are not 
required to be steady burning while the turn signal is in use. Amber 
Class 2 or Class 3, 360 degree warning lamps must meet SAE J845--360 
Degree Warning Lamp for Authorized Emergency, Maintenance and Service 
Vehicles, March 1992. Class 1, 360 degree warning lamps are prohibited. 
Amber flashing warning lamps must meet SAE J595--Flashing Warning Lamps 
for Authorized Emergency, Maintenance and Service Vehicles, January 
1990. Amber Class 2 or Class 3 gaseous discharge warning lamps must 
meet SAE J1318 Gaseous Discharge Warning Lamp for Authorized Emergency, 
Maintenance, and Service Vehicles, April 1986. Class 1 gaseous 
discharge warning lamps are prohibited. (See Sec. 393.7(b) for 
information on the incorporation by reference and availability of these 
documents.)
    (f) Stop lamp operation. The stop lamps on each vehicle shall be 
activated upon application of the service brakes. The stop lamps are 
not required to be activated when the emergency feature of the trailer 
brakes is used or when the stop lamp is optically combined with the 
turn signal and the turn signal is in use.
    18. Section 393.26 is amended by revising paragraphs (a), (b), (c), 
and (d) and introductory text to read as follows:


Sec. 393.26  Requirements for reflex reflectors.

    (a) Mounting. Reflex reflectors shall be mounted at the locations 
required by Sec. 393.11. In the case of motor vehicles so constructed 
that requirement for a 381 mm (15-inch) minimum height above the road 
surface is not practical, the reflectors shall be mounted as high as 
practicable. All permanent reflex reflectors shall be securely mounted 
on a rigid part of the vehicle. Temporary reflectors on projecting 
loads must be securely mounted to the load and are not required to be 
permanently mounted to a part of the vehicle. Temporary reflex 
reflectors on vehicles transported in driveaway-towaway operations must 
be firmly attached.
    (b) Specifications. All required reflex reflectors (except reflex 
reflectors on projecting loads, vehicles transported in a driveaway-
towaway operation, converter dollies and pole trailers) on vehicles 
manufactured on or after December 25, 1968, shall meet the applicable 
requirements of FMVSS No. 108 in effect on the date of manufacture of 
the vehicle. Reflex reflectors on projecting loads, vehicles 
transported in a driveaway-towaway operation, and all reflex reflectors 
on converter dollies, pole trailers must conform to SAE J594--Reflex 
Reflectors, July 1995.
    (c) Substitute material for side reflex reflectors. Reflective 
material conforming to ASTM D 4956-90, Standard Specification for 
Retroreflective Sheeting for Traffic Control, may be used in lieu of 
reflex reflectors if the material as used on the vehicle, meets the 
performance standards in either Table I or Table IA of SAE J594--Reflex 
Reflectors, July 1995. (See Sec. 393.7(b) for information on the 
incorporation by reference and availability of these documents.)
    (d) Use of additional retroreflective surfaces. Additional 
retroreflective surfaces may be used in conjunction with, but not in 
lieu of the reflex reflectors required in subpart B of part 393, and 
the substitute material for side reflex reflectors allowed by paragraph 
(c) of this section, provided:
* * * * *
    19. Section 393.28 is revised to read as follows:

[[Page 18194]]

Sec. 393.28  Wiring systems.

    Electrical wiring shall be installed and maintained to conform to 
SAE J1292--Automobile, Truck, Truck-Tractor, Trailer, and Motor Coach 
Wiring, October 1981. (See Sec. 393.7(b) for information on the 
incorporation by reference and availability of this document.)


Sec. 393.27, 393.29, 393.31, 393.32, and 393.33  [Removed and Reserved]

    20. Sections 393.27, 393.29, 393.31, 393.32, and 393.33 are removed 
and reserved.
    21. Section 393.40 is revised to read as follows:


Sec. 393.40  Required brake systems.

    (a) Each commercial motor vehicle must have brakes adequate to stop 
and hold the vehicle or combination of motor vehicles. Each commercial 
motor vehicle must meet the applicable service, parking, and emergency 
brake system requirements provided in this section.
    (b) Service brakes--(1) Hydraulic brake systems. Motor vehicles 
equipped with hydraulic brake systems and manufactured on or after 
September 2, 1983, must, at a minimum, have a service brake system that 
meets the requirements of FMVSS No. 105 in effect on the date of 
manufacture. Motor vehicles which were not subject to FMVSS No. 105 on 
the date of manufacture must have a service brake system that meets the 
applicable requirements of Secs. 393.42, 393.48, 393.49, 393.51, and 
393.52 of this subpart.
    (2) Air brake systems. Buses, trucks and truck-tractors equipped 
with air brake systems and manufactured on or after March 1, 1975, and 
trailers manufactured on or after January 1, 1975, must, at a minimum, 
have a service brake system that meets the requirements of FMVSS No. 
121 in effect on the date of manufacture. Motor vehicles which were not 
subject to FMVSS No. 121 on the date of manufacture must have a service 
brake system that meets the applicable requirements of Secs. 393.42, 
393.48, 393.49, 393.51, and 393.52 of this subpart.
    (3) Vacuum brake systems. Motor vehicles equipped with vacuum brake 
systems must have a service brake system that meets the applicable 
requirements of Secs. 393.42, 393.48, 393.49, 393.51, and 393.52 of 
this subpart.
    (4) Electric brake systems. Motor vehicles equipped with electric 
brake systems must have a service brake system that meets the 
applicable requirements of Secs. 393.42, 393.48, 393.49 and 393.52 of 
this subpart.
    (c) Parking brakes. Each commercial motor vehicle must be equipped 
with a parking brake system that meets the applicable requirements of 
Sec. 393.41.
    (d) Emergency brakes-- partial failure of service brakes--(1) 
Hydraulic brake systems. Motor vehicles manufactured on or after 
September 2, 1983, and equipped with a split service brake system must, 
at a minimum, meet the partial failure requirements of FMVSS No. 105 in 
effect on the date of manufacture.
    (2) Air brake systems. Buses, trucks and truck tractors 
manufactured on or after March 1, 1975, and trailers manufactured on or 
after January 1, 1975, must be equipped with an emergency brake system 
which, at a minimum, meets the requirements of FMVSS No. 121 in effect 
on the date of manufacture.
    (3) Vehicles not subject to FMVSS Nos. 105 and 121 on the date of 
manufacture. Buses, trucks and truck tractors not subject to FMVSS Nos. 
105 or 121 on the date of manufacture must meet the requirements of 
Sec. 393.40(e). Trailers not subject to FMVSS No. 121 at the time of 
manufacture must meet the requirements of Sec. 393.43.
    (e) Emergency brakes, vehicles manufactured on or after July 1, 
1973. (1) A bus, truck, truck tractor, or a combination of motor 
vehicles manufactured on or after July 1, 1973, and not covered under 
paragraphs (d)(1) or (d)(2) of this section, must have an emergency 
brake system which consists of emergency features of the service brake 
system or an emergency system separate from the service brake system. 
The emergency brake system must meet the applicable requirements of 
Secs. 393.43 and 393.52.
    (2) A control by which the driver applies the emergency brake 
system must be located so that the driver can operate it from the 
normal seating position while restrained by any seat belts with which 
the vehicle is equipped. The emergency brake control may be combined 
with either the service brake control or the parking brake control. 
However, all three controls may not be combined.
    (f) Interconnected systems. (1) If the brake systems required by 
Sec. 393.40(a) are interconnected in any way, they must be designed, 
constructed, and maintained so that in the event of a failure of any 
part of the operating mechanism of one or more of the systems (except 
the service brake actuation pedal or valve), the motor vehicle will 
have operative brakes and, for vehicles manufactured on or after July 
1, 1973, be capable of meeting the requirements of Sec. 393.52(b).
    (2) A motor vehicle to which the requirements of FMVSS No. 105 (49 
CFR 571.105, S5.1.2), dealing with partial failure of the service 
brake, applied at the time of manufacture meets the requirements of 
Sec. 393.40(f)(1) if the motor vehicle is maintained in conformity with 
FMVSS No. 105 and the motor vehicle is capable of meeting the 
requirements of Sec. 393.52(b), except in the case of a structural 
failure of the brake master cylinder body.
    (3) A bus is considered to meet the requirements of 
Sec. 393.40(f)(1) if it meets the requirements of Sec. 393.44 and 
Sec. 393.52(b).
    22. Section 393.41 is revised to read as follows:


Sec. 393.41  Parking brake system.

    (a) Hydraulic-braked vehicles manufactured on or after September 2, 
1983. Each truck and bus (other than a school bus) with a GVWR of 4,536 
kg (10,000 pounds) or less which is subject to this part and school 
buses with a GVWR greater than 4,536 kg (10,000 pounds) shall be 
equipped with a parking brake system as required by FMVSS No. 105 (49 
CFR 571.105, S5.2) in effect at the time of manufacture. The parking 
brake shall be capable of holding the vehicle or combination of 
vehicles stationary under any condition of loading in which it is found 
on a public road (free of ice and snow). Hydraulic-braked vehicles 
which were not subject to the parking brake requirements of FMVSS No. 
105 (49 CFR 571.105, S5.2) must be equipped with a parking brake system 
that meets the requirements of paragraph (c) of this section.
    (b) Air-braked power units manufactured on or after March 1, 1975, 
and air-braked trailers manufactured on or after January 1, 1975. Each 
air-braked bus, truck and truck tractor manufactured on and after March 
1, 1975, and each air-braked trailer except an agricultural commodity 
trailer, converter dolly, heavy hauler trailer or pulpwood trailer, 
shall be equipped with a parking brake system as required by FMVSS No. 
121 (49 CFR 571.121, S5.6) in effect at the time of manufacture. The 
parking brake shall be capable of holding the vehicle or combination of 
vehicles stationary under any condition of loading in which it is found 
on a public road (free of ice and snow). An agricultural commodity 
trailer, heavy hauler or pulpwood trailer shall carry sufficient 
chocking blocks to prevent movement when parked.
    (c) Vehicles not subject to FMVSS Nos. 105 and 121 on the date of 
manufacture and all vacuum braked vehicles and electric braked 
trailers. (1)

[[Page 18195]]

All hydraulic-braked motor vehicles not subject to FMVSS No. 105 (49 
CFR 571.105, S5.2) at the time of manufacture; hydraulic-braked 
trailers; air-braked buses, trucks and truck tractors manufactured 
before March 1, 1975; air-braked trailers (other than agricultural 
commodity, heavy hauler, or pulpwood trailers) manufactured before 
January 1, 1975; and vacuum braked motor vehicles and electric braked 
trailers (regardless of the date of manufacture) shall be equipped with 
a parking brake system adequate to hold the vehicle or combination on 
any grade on which it is operated, under any condition of loading in 
which it is found on a public road (free of ice and snow).
    (2) The parking brake system shall, at all times, be capable of 
being applied by either the driver's muscular effort or by spring 
action. If other energy is used to apply the parking brake, there must 
be an accumulation of that energy isolated from any common source and 
used exclusively for the operation of the parking brake. Exception: 
This paragraph shall not be applicable to air-applied, mechanically-
held parking brake systems which meet the parking brake requirements of 
FMVSS No. 121 (49 CFR 571.121, S5.6).
    (3) The parking brake system shall be held in the applied position 
by energy other than fluid pressure, air pressure, or electric energy. 
The parking brake system shall not be capable of being released unless 
adequate energy is available to immediately reapply the parking brake 
with the required effectiveness.
    23. Section 393.42 is amended by revising paragraph (b) to read as 
follows:


Sec. 393.42  Brakes required on all wheels.

* * * * *
    (b) Exception. (1) Trucks or truck tractors having three or more 
axles and manufactured before July 25, 1980, are not required to have 
brakes on the front wheels. However, these vehicles must meet the 
requirements of Sec. 393.52.
    (2) Motor vehicles being towed in a driveaway-towaway operation are 
not required to have operative brakes provided the combination of 
vehicles meets the requirements of Sec. 393.52. This exception is not 
applicable to:
    (i) Any motor vehicle towed by means of a tow-bar when another 
motor vehicle is full-mounted on the towed vehicle; and
    (ii) Any combination of motor vehicles utilizing three or more 
saddle-mounts.
    (3) Any semitrailer or pole trailer (laden or unladen) with a gross 
weight of 1,361 kg (3,000 pounds) or less which is subject to this part 
is not required to be equipped with brakes if the axle weight of the 
towed vehicle does not exceed 40 percent of the sum of the axle weights 
of the towing vehicle.
    (4) Any full trailer or four-wheel pole trailer (laden or unladen) 
with a gross weight of 1,361 kg (3,000 pounds) or less which is subject 
to this part is not required to be equipped with brakes if the sum of 
the axle weights of the towed vehicle does not exceed 40 percent of the 
sum of the axle weights of the towing vehicle.
    (5) Brakes are not required on the steering axle of a three-axle 
dolly which is steered by a co-driver.
    (6) Loaded housemoving dollies, specialized trailers and dollies 
used to transport industrial furnaces, reactors, and similar motor 
vehicles are not required to be equipped with brakes, provided the 
speed at which the combination of vehicles will be operated does not 
exceed 32 km/hour (20 mph) and brakes on the combination of vehicles 
are capable of stopping the combination within 12.2 meters (40 feet) 
from the speed at which the vehicle is being operated or 32 km/hour (20 
mph), whichever is less.
* * * * *
    24. Section 393.43 is amended by revising paragraphs (a), (d) and 
(f) and by adding initial subheadings to paragraphs (b), (c), and (e) 
to read as follows:


Sec. 393.43  Breakaway and emergency braking.

    (a) Towing vehicle protection system. Every motor vehicle, if used 
to tow a trailer equipped with brakes, shall be equipped with a means 
for providing that in the case of a breakaway of the trailer, the 
service brakes on the towing vehicle will be capable of stopping the 
towing vehicle. For air braked towing units, the tractor protection 
valve or similar device shall operate automatically when the air 
pressure on the towing vehicle is between 138 kPa and 310 kPa (20 psi 
and 45 psi).
    (b) Emergency brake requirements, air brakes. * * *
    (c) Emergency brake requirements, vacuum brakes. * * *
    (d) Breakaway braking requirements for trailers. Every trailer 
required to be equipped with brakes shall have brakes which apply 
automatically and immediately upon breakaway from the towing vehicle. 
All brakes with which the trailer is required to be equipped must be 
applied upon breakaway from the towing vehicle. The brakes must remain 
in the applied position for at least 15 minutes.
    (e) Emergency valves. * * *
    (f) Exception. The requirements of paragraphs (b), (c) and (d) of 
this section shall not be applicable to commercial motor vehicles being 
transported in driveaway-towaway operations.
    25. Section 393.45 is revised to read as follows:


Sec. 393.45  Brake tubing and hoses; hose assemblies and end fittings.

    (a) General construction requirements for tubing and hoses, 
assemblies, and end fittings. All brake tubing and hoses, brake hose 
assemblies, and brake hose end fittings must meet the applicable 
requirements of FMVSS No. 106 (49 CFR 571.106).
    (b) Special rule for coiled nylon brake tubing in air brake 
systems. Coiled nylon brake hose or hose assemblies which meet SAE 
J844, Nonmetallic Air Brake System Tubing, October 1994, are not 
required to meet 49 CFR 571.106, S7.3.6 (length change), S7.3.10 
(tensile strength), and S7.3.11 (tensile strength of an assembly after 
immersion in water) of FMVSS No. 106.
    (c) Brake tubing and hose installation. Brake tubing and hose 
must--
    (1) Be long and flexible enough to accommodate without damage all 
normal motions of the parts to which it is attached;
    (2) Be secured against chaffing, kinking, or other mechanical 
damage; and
    (3) Be installed in a manner that prevents it from contacting the 
vehicle's exhaust system or any other source of high temperatures.
    (d) Nonmetallic brake tubing. Coiled nonmetallic brake tubing may 
be used for connections between towed and towing motor vehicles or 
between the frame of a towed vehicle and the unsprung subframe of an 
adjustable axle of the motor vehicle if--
    (1) The coiled tubing has a straight segment (pigtail) at each end 
that is at least 51 mm (2 inches) in length and is encased in a spring 
guard or similar device which prevents the tubing from kinking at the 
fitting at which it is attached to the vehicle; and
    (2) The spring guard or similar device has at least 51 mm (2 
inches) of closed coils or similar surface at its interface with the 
fitting and extends at least 38 mm (1\1/2\ inches) into the coiled 
segment of the tubing from its straight segment.
    (e) Brake tubing and hose connections. All connections for air, 
vacuum, or hydraulic braking systems shall be installed so as to ensure 
an attachment free of leaks, constrictions or other conditions which 
would adversely affect the performance of the brake system.

[[Page 18196]]

Sec. 393.46  [Removed and Reserved]

    26. Section 393.46 is removed and reserved.
    27. Section 393.47 is revised to read as follows:


Sec. 393.47  Brake actuators, slack adjusters, linings/pads and drums/
rotors.

    (a) General requirements. Brake components must be constructed, 
installed and maintained to prevent excessive fading and grabbing. The 
means of attachment and physical characteristics must provide for safe 
and reliable stopping of the commercial motor vehicle.
    (b) Brake chambers. The service brake chambers and spring brake 
chambers on each end of an axle must be the same size.
    (c) Slack adjusters. The effective length of the slack adjuster on 
each end of an axle must be the same.
    (d) Linings and pads. The thickness of the brake linings or pads 
shall meet the applicable requirements of this paragraph --
    (1) Steering axle brakes. The brake lining/pad thickness on the 
steering axle of a truck, truck-tractor or bus shall not be less than 
4.8 mm (\3/16\ inch) at the shoe center for a shoe with a continuous 
strip of lining; less than 6.4 mm (\1/4\ inch) at the shoe center for a 
shoe with two pads; or worn to the wear indicator if the lining is so 
marked, for air drum brakes. The steering axle brake lining/pad 
thickness shall not be less than 3.2 mm (\1/8\ inch) for air disc 
brakes, or 1.6 mm (\1/16\ inch) or less for hydraulic disc, drum and 
electric brakes.
    (2) Non-steering axle brakes. An air braked commercial motor 
vehicle shall not be operated with brake lining/pad thickness less than 
6.4 mm (\1/4\ inch) or to the wear indicator if the lining is so marked 
(measured at the shoe center for drum brakes); or less than 3.2 mm (\1/
8\ inch) for disc brakes. Hydraulic or electric braked commercial motor 
vehicles shall not be operated with a lining/pad thickness less than 
1.6 mm (\1/16\ inch) (measured at the shoe center) for disc or drum 
brakes.
    (e) Clamp and roto-chamber brake actuator readjustment limits. The 
pushrod travel for clamp and roto-chamber type actuators must be less 
than 80 percent of the rated strokes listed in SAE J1817--Long Stroke 
Air Brake Actuator Marking, June 1991, or 80 percent of the rated 
stroke marked on the brake chamber by the chamber manufacturer, or the 
readjustment limit marked on the brake chamber by the chamber 
manufacturer. The pushrod travel for Type 16 and 20 long stroke clamp 
type brake actuators must be less than 51 mm (2 inches) or 80 percent 
of the rated stroke marked on the brake chamber by the chamber 
manufacturer, or the readjustment limit marked on the brake chamber by 
the chamber manufacturer.
    (f) Wedge brake adjustment. The movement of the scribe mark on the 
lining shall not exceed 1.6 mm (\1/16\ inch).
    (g) Drums and rotors. The thickness of the drums or rotors shall 
not be less than the limits established by the brake drum or rotor 
manufacturer.
    28. Section 393.48 is revised to read as follows:


Sec. 393.48  Brakes to be operative.

    (a) General rule. Except as provided in paragraphs (b) and (c) of 
this section, all brakes with which a commercial motor vehicle is 
equipped must be operable at all times.
    (b) Devices to reduce or remove front-wheel braking effort. A 
commercial motor vehicle may be equipped with a device to reduce the 
front wheel braking effort (or in the case of a three-axle truck or 
truck tractor manufactured before March 1, 1975, a device to remove the 
front-wheel braking effort) if that device meets the applicable 
requirements of paragraphs (b) (1) and (2) of this section.
    (1) Manually operated devices. Manually operated devices to reduce 
or remove front-wheel braking effort may only be used on buses, trucks, 
and truck tractors manufactured before March 1, 1975. Such devices must 
not be used unless the vehicle is being operated under adverse 
conditions such as wet, snowy, or icy roads.
    (2) Automatic devices. Automatic devices must not reduce the front-
wheel braking force by more than 50 percent of the braking force 
available when the automatic device is disconnected (regardless of 
whether or not an antilock system failure has occurred on any axle). 
The device must not be operable by the driver except upon application 
of the control that activates the braking system. The device must not 
be operable when the brake control application pressure exceeds 85 psig 
(for vehicles equipped with air brakes) or 85 percent of the maximum 
system pressure (for vehicles which are not equipped with air brakes).
    (c) Exception. Paragraph (a) of this section does not apply to--
    (1) A towed vehicle with disabling damage as defined in Sec. 390.5;
    (2) A vehicle which is towed in a driveaway-towaway operation and 
is included in the exemption to the requirement for brakes on all 
wheels, Sec. 393.42(b);
    (3) Unladen converter dollies with a gross weight of 1,361 kg 
(3,000 lbs) or less, and manufactured prior to March 1, 1998;
    (4) The steering axle of a three-axle dolly which is steered by a 
co-driver;
    (5) Loaded house moving dollies, specialized trailers and dollies 
used to transport industrial furnaces, reactors, and similar motor 
vehicles provided the speed at which the combination of vehicles will 
be operated does not exceed 32 km/hour (20 mph) and brakes on the 
combination of vehicles are capable of stopping the combination within 
12.2 meters (40 feet) from the speed at which the vehicle is being 
operated or 32 km/hour (20 mph), whichever is less.
    (6) Raised lift axles. Brakes on lift axles need not be capable of 
being operated while the lift axle is raised. However, brakes on lift 
axles must be capable of being applied whenever the lift axle is 
lowered and the tires contact the roadway.
    29. Section 393.50 is revised to read as follows:


Sec. 393.50  Reservoirs required.

    (a) Reservoir capacity for air-braked power units manufactured on 
or after March 1, 1975, and air-braked trailers manufactured on or 
after January 1, 1975. Buses, trucks, and truck-tractors must meet the 
reservoir requirements of FMVSS No. 121, (49 CFR 571.121, S5.1.2), in 
effect on the date of manufacture.
    (b) Reservoir capacity for air-braked vehicles not subject to FMVSS 
No. 121 on the date of manufacture and all vacuum braked vehicles. Each 
motor vehicle using air or vacuum braking must have either reserve 
capacity, or a reservoir, that would enable the driver to make a full 
service brake application with the engine stopped without depleting the 
air pressure or vacuum below 70 percent of that indicated by the air or 
vacuum gauge immediately before the brake application is made. For the 
purposes of this paragraph, a full service brake application means 
depressing the brake pedal or treadle valve to the limit of its travel.
    (c) Safeguarding of air and vacuum. Each service reservoir system 
on a motor vehicle shall be protected against a loss of air pressure or 
vacuum due to a failure or leakage in the system between the service 
reservoir and the source of air pressure or vacuum, by check valves or 
equivalent devices whose proper functioning can be checked without 
disconnecting any air or vacuum line, or fitting.
    (d) Drain valves for air braked vehicles. Each reservoir must have 
a condensate drain valve that can be manually operated. Automatic

[[Page 18197]]

condensate drain valves may be used provided they may be operated 
manually, or a manual means of draining the reservoirs is retained.
    30. Section 393.51 is revised to read as follows:


Sec. 393.51  Warning signals, air pressure and vacuum gauges.

    (a) General rule. Every bus, truck and truck tractor, except as 
provided in paragraph (f) of this section, must be equipped with a 
signal that provides a warning to the driver when a failure occurs in 
the vehicle's service brake system. The warning signal must meet the 
applicable requirements of paragraphs (b), (c), (d) or (e) of this 
section.
    (b) Hydraulic brakes. Vehicles manufactured on or after September 
1, 1975, must meet the brake system indicator lamp requirements of 
FMVSS No. 105 571.105, (49 CFR (S5.3)), applicable to the vehicle on 
the date of manufacture. Vehicles manufactured on or after July 1, 1973 
but before September 1, 1975, or to which FMVSS No. 105 (49 CFR 
571.105), was not applicable on the date of manufacture, must have a 
warning signal which operates before or upon application of the brakes 
in the event of a hydraulic-type complete failure of a partial system. 
The signal must be either visible within the driver's forward field of 
view or audible. The signal must be continuous.

    (Note: FMVSS No. 105 was applicable to trucks and buses from 
September 1, 1975 to October 12, 1976, and from September 1, 1983, 
to the present. FMVSS No. 105 was not applicable to trucks and buses 
manufactured between October 12, 1976, and September 1, 1983. Motor 
carriers have the option of equipping those vehicles to meet either 
the indicator lamp requirements of FMVSS No. 105, or the indicator 
lamp requirements specified in this paragraph for vehicles which 
were not subject to FMVSS No. 105 on the date of manufacture.)

    (c) Air brakes. A commercial motor vehicle (regardless of the date 
of manufacture) equipped with service brakes activated by compressed 
air (air brakes) or a commercial motor vehicle towing a vehicle with 
service brakes activated by compressed air (air brakes) must be 
equipped with a pressure gauge and a warning signal. Trucks, truck 
tractors, and buses manufactured on or after March 1, 1975, must, at a 
minimum, have a pressure gauge and a warning signal which meets the 
requirements of FMVSS No. 121 (49 CFR 571.121, S5.1.4 for the pressure 
gauge and S5.1.5 for the warning signal) applicable to the vehicle on 
the date of manufacture of the vehicle. Power units to which FMVSS No. 
121 (49 CFR 571.121) was not applicable on the date of manufacture of 
the vehicle must be equipped with--
    (1) A pressure gauge, visible to a person seated in the normal 
driving position, which indicates the air pressure (in kilopascals 
(kPa) or pounds per square inch (psi)) available for braking; and
    (2) A warning signal that is audible or visible to a person in the 
normal driving position and provides a continuous warning to the driver 
whenever the air pressure in the service reservoir system is at 379 kPa 
(55 psi) and below, or one-half of the compressor governor cutout 
pressure, whichever is less.
    (d) Vacuum brakes. A commercial motor vehicle (regardless of the 
date it was manufactured) having service brakes activated by vacuum or 
a vehicle towing a vehicle having service brakes activated by vacuum 
must be equipped with--
    (1) A vacuum gauge, visible to a person seated in the normal 
driving position, which indicates the vacuum (in millimeters or inches 
of mercury) available for braking; and
    (2) A warning signal that is audible or visible to a person in the 
normal driving position and provides a continuous warning to the driver 
whenever the vacuum in the vehicle's supply reservoir is less than 203 
mm (8 inches) of mercury.
    (e) Hydraulic brakes applied or assisted by air or vacuum. Each 
vehicle equipped with hydraulically activated service brakes which are 
applied or assisted by compressed air or vacuum, and to which FMVSS No. 
105 was not applicable on the date of manufacture, must be equipped 
with a warning signal that conforms to paragraph (b) of this section 
for the hydraulic portion of the system; paragraph (c) of this section 
for the air assist/air applied portion; or paragraph (d) of this 
section for the vacuum assist/vacuum applied portion. This paragraph 
shall not be construed as requiring air pressure gauges or vacuum 
gauges, only warning signals.
    (f) Exceptions. The rules in paragraphs (c), (d) and (e) of this 
section do not apply to property carrying commercial motor vehicles 
which have less than three axles and--
    (1) Were manufactured before July 1, 1973, and
    (2) Have a manufacturer's gross vehicle weight rating less than 
4,536 kg (10,001 pounds).
    31. Section 393.60 is revised to read as follows:


Sec. 393.60  Glazing in specified openings.

    (a) Glazing material. Glazing material used in windshields, windows 
and doors on a motor vehicle manufactured on or after December 25, 
1968, shall at a minimum meet the requirements of FMVSS No. 205 in 
effect on the date of manufacture of the motor vehicle. The glazing 
material shall be marked in accordance with FMVSS No. 205 (49 CFR 
571.205, S6).
    (b) Windshields required. Each bus, truck and truck-tractor shall 
be equipped with a windshield. Each windshield or portion of a multi-
piece windshield shall be mounted using the full periphery of the 
glazing material.
    (c) Windshield condition. With the exception of the conditions 
listed in paragraphs (c)(1), (c)(2), and (c)(3) of this section, each 
windshield shall be free of discoloration or damage in the area 
extending upward from the height of the top of the steering wheel 
(excluding a 51 mm (2 inch) border at the top of the windshield) and 
extending from a 25 mm (1 inch) border at each side of the windshield 
or windshield panel. Exceptions:
    (1) Coloring or tinting which meets the requirements of paragraph 
(d) of this section;
    (2) Any crack less than 6 mm (\1/4\ inch) wide, if not intersected 
by any other cracks;
    (3) Any damaged area which can be covered by a disc, 19 mm (\3/4\ 
inch) in diameter, if not closer than 76 mm (3 inches) to any other 
similarly damaged area.
    (d) Coloring or tinting of windshields and windows. Coloring or 
tinting of windshields and the windows to the immediate right and left 
of the driver is allowed provided the parallel luminous transmittance 
through the colored or tinted glazing is not less than 70 percent of 
the light at normal incidence in those portions of the windshield or 
windows which are marked as having a parallel luminous transmittance of 
not less than 70 percent. The transmittance restriction does not apply 
to other windows on the commercial motor vehicle.
    (e) Prohibition on obstructions to the drivers field of view--(1) 
Devices mounted at the top of the windshield. Antennas, transponders, 
and similar devices must not be mounted more than 152 mm (6 inches) 
from the upper edge of the windshield. These devices must be located 
outside the area swept by the windshield wipers, and outside the 
driver's sight lines to the road and highway signs and signals.
    (2) Decals and stickers mounted on the windshield. Commercial 
Vehicle Safety Alliance (CVSA) inspection

[[Page 18198]]

decals, and stickers and/or decals required under Federal or State laws 
may be placed at the bottom or sides of the windshield provided such 
decals or stickers are located outside the area swept by the windshield 
wipers, and outside the driver's sight lines to the road and highway 
signs or signals.
    32. Section 393.61 is revised to read as follows:


Sec. 393.61  Truck and truck tractor window construction.

    Each truck and truck tractor (except trucks engaged in armored car 
service) shall have at least one window on each side of the driver's 
compartment. Each window must have a minimum area of 1,290 cm\2\ (200 
in\2\) formed by a rectangle 33 cm by 45 cm (13 inches by 17\3/4\ 
inches). The maximum radius of the corner arcs shall not exceed a 152 
mm (6 inches). The long axis of the rectangle shall not make an angle 
of more than 45 degrees with the surface on which the unladen vehicle 
stands. If the cab is designed with a folding door or doors or with 
clear openings where doors or windows are customarily located, no 
windows shall be required in those locations.
    33. Section 393.62 is revised to read as follows:


Sec. 393.62  Emergency exits for buses.

    (a) Buses manufactured on or after September 1, 1994. Each bus with 
a GVWR of 4,536 kg (10,000 pounds) or less must meet the emergency exit 
requirements of FMVSS No. 217 (49 CFR 571.217, S5.2.2.3) in effect on 
the date of manufacture. Each bus with a GVWR of more than 4,536 kg 
(10,000 pounds) must have emergency exits which meet the applicable 
emergency exit requirements of FMVSS No. 217 (49 CFR 571.217, S5.2.2 or 
S5.2.3) in effect on the date of manufacture.
    (b) Buses manufactured on or after September 1, 1973, but before 
September 1, 1994.
    (1) Each bus (including a school bus used in interstate commerce 
for non-school bus operations) with a GVWR of more than 4,536 kg 
(10,000 lbs) must meet the requirements of FMVSS No. 217, (49 CFR 571. 
217 S5.2.2) in effect on the date of manufacture.
    (2) Each bus (including a school bus used in interstate commerce 
for non-school bus operations) with a GVWR of 4,536 kg (10,000 lbs) or 
less must meet the requirements of FMVSS No. 217 (49 CFR 571.217, 
S5.2.2.3) in effect on the date of manufacture.
    (c) Buses manufactured before September 1, 1973. For each seated 
passenger space provided, inclusive of the driver there shall be at 
least 432 cm2 (67 square inches) of glazing if such glazing is not 
contained in a push-out window; or, at least 432 cm2 (67 square 
inches) of free opening resulting from opening of a push-out type 
window. No area shall be included in this minimum prescribed area 
unless it will provide an unobstructed opening of at least 1,290 
cm2 (200 in2) formed by a rectangle 33 cm by 45 cm (13 inches 
by 17-3/4 inches). The maximum radius of the corner arcs shall not 
exceed 152 mm (6 inches). The long axis of the rectangle shall not make 
an angle of more than 45 degrees with the surface on which the unladen 
vehicle stands. The area shall be measured either by removal of the 
glazing if not of the push-out type, or of the movable sash if of the 
push-out type. The exit must comply with paragraph (d) of this section. 
Each side of the bus must have at least 40 percent of emergency exit 
space required by this paragraph.
    (d) Laminated safety glass/push-out window requirements for buses 
manufactured before September 1, 1973. Emergency exit space used to 
satisfy the requirements of paragraph (c) of this section must have 
laminated safety glass or push-out windows designed and maintained to 
yield outward to provide a free opening.
    (1) Safety glass. Laminated safety glass must meet Test No. 25, 
Egress, of American National Standard for Safety Glazing Materials for 
Glazing Motor Vehicles Operating on Land Highways--Safety Code, Z26.1-
1990.
    (2) Push-out windows. Each push-out window shall be releasable by 
operating no more than two mechanisms and allow manual release of the 
exit by a single occupant. For mechanisms which require rotary or 
straight (parallel to the undisturbed exit surface) motions to operate 
the exit, no more than 89 Newtons (20 pounds) of force shall be 
required to release the exit. For exits which require a straight motion 
perpendicular to the undisturbed exit surface, no more than 267 Newtons 
(60 pounds) shall be required to release the exit.
    (e) Emergency exit identification. Each bus and each school bus 
used in interstate commerce for non-school bus operations, manufactured 
on or after September 1, 1973, shall meet the applicable emergency exit 
identification or marking requirements of FMVSS No. 217, (49 CFR 571, 
217, S5.5), in effect on the date of manufacture. The emergency exits 
and doors on all buses (including school buses used in interstate 
commerce for non-school bus operations) must be marked ``Emergency 
Exit'' or ``Emergency Door'' followed by concise operating instructions 
describing each motion necessary to unlatch or open the exit located 
within 152 mm (6 inches) of the release mechanism.
    (f) Exception for the transportation of prisoners. The requirements 
of this section do not apply to buses used exclusively for the 
transportation of prisoners.


Sec. 393.63  [Removed and Reserved]

    34. Section 393.63 is removed and reserved.
    35. Section 393.67 is amended by removing the footnote to 
paragraphs (d) and (e); by revising the introductory text of paragraphs 
(a), (d), and (e); and by revising paragraph (f)(2) to read as follows:


Sec. 393.67  Liquid fuel tanks.

    (a) Application of the rules in this section. The rules in this 
section apply to tanks containing or supplying fuel for the operation 
of commercial motor vehicles or for the operation of auxiliary 
equipment installed on, or used in connection with commercial motor 
vehicles.
* * * * *
    (d) Liquid fuel tank tests. Each liquid fuel tank must be capable 
of passing the tests specified in paragraphs (d)(1) and (2) of this 
section. The specified tests are a measure of performance only. 
Alternative procedures which assure that equipment meets the required 
performance standards may be used.
* * * * *
    (e) Side-mounted liquid fuel tank tests. Each side-mounted liquid 
fuel tank must be capable of passing the tests specified in paragraphs 
(e)(1) and (2) of this section and the test specified in paragraphs 
(d)(1) and (2) of this section. The specified tests are a measure of 
performance only. Alternative procedures which assure that equipment 
meets the required performance criteria may be used.
* * * * *
    (f) * * *
    (2) The manufacturer's name on tanks manufactured on and after July 
1, 1989, and means of identifying the facility at which the tank was 
manufactured, and
* * * * *
    36. Section 393.68 is added to part 393 and reads as follows:


Sec. 393.68  Compressed natural gas fuel containers.

    (a) Applicability. The rules in this section apply to compressed 
natural gas (CNG) fuel containers used for supplying fuel for the 
operation of commercial motor vehicles or for the operation of 
auxiliary equipment

[[Page 18199]]

installed on, or used in connection with commercial motor vehicles.
    (b) CNG containers manufactured on or after March 26, 1995. Any 
motor vehicle manufactured on or after March 26, 1995, and equipped 
with a CNG fuel tank must meet the CNG container requirements of FMVSS 
No. 304 (49 CFR 571.304) in effect at the time of manufacture of the 
vehicle.
    (c) Labeling. Each CNG fuel container shall be permanently labeled 
in accordance with the requirements of FMVSS No. 304, (49 CFR 571.304, 
S7.4).
    37. Section 393.70 is amended by revising paragraph (d)(8) to read 
as follows:


Sec. 393.70  Coupling devices and towing methods, except for driveaway-
towaway operation.

    (d) * * * (8)(i) When two safety devices, including two safety 
chains or cables, are used and are attached to the towing vehicle at 
separate points, the points of attachment on the towing vehicle shall 
be located equally distant from, and on opposite sides of, the 
longitudinal centerline of the towing vehicle.
    (ii) Where two chains or cables are attached to the same point on 
the towing vehicle, and where a bridle or a single chain or cable is 
used, the point of attachment must be on the longitudinal centerline or 
within 152 mm (6 inches) to the right of the longitudinal centerline of 
the towing vehicle.
    (iii) A single safety device, other than a chain or cable, must 
also be attached to the towing vehicle at a point on the longitudinal 
centerline or within 152 mm (6 inches) to the right of the longitudinal 
centerline of the towing vehicle.
    38. Section 393.71 is amended by revising paragraphs (a)(2) and (g) 
and the heading of paragraph (b) and by adding paragraph (b)(3):


Sec. 393.71  Coupling devices and towing methods, driveaway-towaway 
operations.

    (a) * * *
    (2) No more than one tow-bar or ball-and-socket type coupling 
device may be used in any combination.
* * * * *
    (b) Carrying vehicles on towing vehicles, and multiple saddle-
mounts. * * *
* * * * *
    (3) Saddle-mounted vehicles must be arranged such that the gross 
weight of the vehicles is properly distributed to prevent undue 
interference with the steering, braking, or maneuvering of the 
combination of vehicles.
* * * * *
    (g) Means required for towing. No motor vehicles or combination of 
motor vehicles shall be towed in driveaway-towaway operations by means 
other than a tow-bar, ball-and-socket type coupling device, saddle-
mount connections which meet the requirements of this section, or in 
the case of a semi-trailer equipped with an upper coupler assembly, a 
fifth-wheel meeting the requirements of Sec. 393.70.
* * * * *
    39. Section 393.75 is amended by revising paragraph (e) to read as 
follows:


Sec. 393.75  Tires.

* * * * *
    (e) A regrooved tire with a load-carrying capacity equal to or 
greater than 2,232 kg (4,920 pounds) shall not be used on the front 
wheels of any truck or truck tractor.
* * * * *
    40. Section 393.78 is revised to read as follows:


Sec. 393.78  Windshield wiping and washing systems.

    (a) Vehicles manufactured on or after December 25, 1968. Each bus, 
truck, and truck-tractor manufactured on or after December 25, 1968, 
must have a windshield wiping system that meets the requirements of 
FMVSS No. 104 (49 CFR 571.104, S4.1) in effect on the date of 
manufacture. Each of these vehicles must have a windshield washing 
system that meets the requirements of FMVSS No. 104 (49 CFR 571.104, 
S4.2.2) in effect on the date of manufacture.
    (b) Vehicles manufactured between June 30, 1953, and December 24, 
1968. Each truck, truck-tractor, and bus manufactured between June 30, 
1953, and December 24, 1968, shall be equipped with a power-driven 
windshield wiping system with at least two wiper blades, one on each 
side of the centerline of the windshield. Motor vehicles which depend 
upon vacuum to operate the windshield wipers, shall have the wiper 
system constructed and maintained such that the performance of the 
wipers will not be adversely affected by a change in the intake 
manifold pressure.
    (c) Driveaway-towaway operations. Windshield wiping and washing 
systems need not be in working condition while a commercial motor 
vehicle is being towed in a driveaway-towaway operation.
    41. Section 393.79 is revised to read as follows:


Sec. 393.79  Windshield defrosting and defogging systems.

    (a) Vehicles manufactured on or after December 25, 1968. Each bus, 
truck, and truck-tractor manufactured on or after December 25, 1968, 
must have a windshield defrosting and defogging system that meets the 
requirements of FMVSS No. 103 in effect on the date of manufacture.
    (b) Vehicles manufactured before December 25, 1968. Each bus, 
truck, and truck-tractor shall be equipped with a means for preventing 
the accumulation of ice, snow, frost, or condensation that could 
obstruct the driver's view through the windshield while the vehicle is 
being driven.
    42. Section 393.82 is revised to read as follows:


Sec. 393.82  Speedometer.

    Each bus, truck, and truck-tractor must be equipped with a 
speedometer indicating vehicle speed in miles per hour and/or 
kilometers per hour. The speedometer must be accurate to within plus or 
minus 8 km/hr (5 mph) at a speed of 80 km/hr (50 mph).
    43. Section 393.87 is revised to read as follows:


Sec. 393.87  Warning flags on projecting loads.

    (a) Any commercial motor vehicle transporting a load which extends 
beyond the sides by more than 102 mm (4 inches) or more than 1,219 mm 
(4 feet) beyond the rear must have the extremities of the load marked 
with red or orange fluorescent warning flags. Each warning flag must be 
at least 457 mm (18 inches) square.
    (b) Position of flags. There must be a single flag at the extreme 
rear if the projecting load is two feet wide or less. Two warning flags 
are required if the projecting load is wider than two feet. Flags must 
be located to indicate maximum width of loads which extend beyond the 
sides and/or rear of the vehicle.


Sec. 393.92  [Removed and Reserved]

    44. Section 393.92 is removed and reserved.
    45. Section 393.94 is amended by revising the section heading, by 
removing paragraph (d) and the footnote to paragraph (c), and by 
revising paragraphs (a) and (c)(4) to read as follows:


Sec. 393.94  Interior noise levels in power units.

    (a) Applicability of this section. The interior noise level 
requirements apply to all trucks, truck-tractors, and buses.
* * * * *
    (c) * * *
    (4) The sound level meters used to determine compliance with the 
requirements of this section must meet

[[Page 18200]]

the American National Standards Institute ``Specification for Sound 
Level Meters,'' ANSI S1.4-1983. (See Sec. 393.7(b) for information on 
the incorporation by reference and availability of this document.)
* * * * *
    46. Section 393.95 is amended by revising the introductory text; by 
removing and reserving paragraphs (c), (h) and (i); by revising 
paragraphs (a), and (f) and adding (b) to read as follows:


Sec. 393.95  Emergency equipment on all power units.

    Each truck, truck tractor, and bus (except those towed in 
driveaway-towaway operations) must be equipped as follows:
    (a) Fire extinguishers--(1) Minimum ratings: (i) A power unit that 
is used to transport hazardous materials in a quantity that requires 
placarding (See Sec. 177.823 of this title) must be equipped with a 
fire extinguisher having an Underwriters' Laboratories rating of 10 B:C 
or more.
    (ii) A power unit that is not used to transport hazardous materials 
must be equipped with either:
    (A) A fire extinguisher having an Underwriters' Laboratories rating 
of 5 B:C or more; or
    (B) Two fire extinguishers, each of which has an Underwriters' 
Laboratories rating of 4 B:C or more.
    (2) Labeling and marking. Each fire extinguisher required by this 
section must be labeled or marked by the manufacturer with its 
Underwriters' Laboratories rating.
    (3) Visual Indicators. The fire extinguisher must be designed, 
constructed, and maintained to permit visual determination of whether 
it is fully charged.
    (4) Condition, location, and mounting. The fire extinguisher(s) 
must be filled and located so that it is readily accessible for use. 
The extinguisher(s) must be securely mounted to prevent sliding, 
rolling, or vertical movement relative to the motor vehicle.
    (5) Extinguishing agents. The fire extinguisher must use an 
extinguishing agent that does not need protection from freezing. 
Extinguishing agents must comply with the toxicity provisions of the 
Environmental Protection Agency's Significant New Alternatives Policy 
(SNAP) regulations under 40 CFR Part 82, Subpart G.
    (b) Spare fuses. Power units for which fuses are needed to operate 
any required parts and accessories must have at least one spare fuse 
for each type/size of fuse needed for those parts and accessories.
* * * * *
    (f) Warning devices for stopped vehicles. Except as provided in 
paragraph (g) of this section, one of the following options must be 
used:
    (1) Three bidirectional emergency reflective triangles that conform 
to the requirements of Federal Motor Vehicle Safety Standard No. 125, 
Sec. 571.125 of this title; or
    (2) At least 6 fusees or 3 liquid-burning flares. The vehicle must 
have as many additional fusees or liquid-burning flares as are 
necessary to satisfy the requirements of Sec. 392.22.
    (3) Other warning devices may be used in addition to, but not in 
lieu of, the required warning devices, provided those warning devices 
do not decrease the effectiveness of the required warning devices.
* * * * *
    47. Section 393.102(b)(6) is amended by adding a sentence at the 
end of the paragraph preceding the tables of working load limits to 
read as follows:


Sec. 393.102  Securement systems.

* * * * *
    (b) * * *
    (6) Tables of working load limits. * * * . Welded steel chain which 
is not marked or labeled to enable identification of its grade or 
working load limit shall be considered to have a working load limit 
equal to that for grade 30 proof coil chain.
* * * * *
    48. Section 393.201 is amended by removing paragraph (f) and by 
revising paragraphs (a) and (d) to read as follows:


Sec. 393.201  Frames.

    (a) The frame or chassis of each commercial motor vehicle shall not 
be cracked, loose, sagging or broken.
* * * * *
    (d) Parts and accessories shall not be welded to the frame or 
chassis of a commercial motor vehicle except in accordance with the 
vehicle manufacturer's recommendations. Any welded repair of the frame 
must also be in accordance with the vehicle manufacturer's 
recommendations.
* * * * *
    49. Section 393.207 is amended by adding paragraph (g) to read as 
follows:


Sec. 393.207  Suspension systems.

* * * * *
    (g) Air suspension exhaust controls. The air suspension exhaust 
controls must not have the capability to exhaust air from the 
suspension system of one axle of a two-axle air suspension trailer. 
This paragraph shall not be construed to prohibit--
    (1) Devices that could exhaust air from both axle systems 
simultaneously; or
    (2) Lift axles on multi-axle units.
    50. Section 393.209 is amended by revising paragraph (b) and the 
first sentence of paragraph (d) to read as follows:


Sec. 393.209  Steering wheel systems.

* * * * *
    (b) Steering wheel lash. (1) The steering wheel lash shall not 
exceed the following parameters:

----------------------------------------------------------------------------------------------------------------
       Steering wheel diameter             Manual steering system                Power steering system          
----------------------------------------------------------------------------------------------------------------
406 mm or less (16 inches or less)...  51 mm (2 inches).............  108 mm (4\1/4\ inches).                   
457 mm (18 inches)...................  57 mm (2\1/4\ inches)........  121 mm (4\3/4\ inches).                   
483 mm (19 inches)...................  60 mm (2\3/8\ inches)........  127 mm (5 inches).                        
508 mm (20 inches)...................  64 mm (2\1/2\ inches)........  133 mm (5\1/4\ inches).                   
533 mm (21 inches)...................  67 mm (2\5/8\ inches)........  140 mm (5\1/2\ inches).                   
559 mm (22 inches)...................  70 mm (2\3/4\ inches)........  146 mm (5\3/4\ inches).                   
----------------------------------------------------------------------------------------------------------------

    (2) For steering wheel diameters not listed in paragraph (b)(1) of 
this section the steering wheel lash shall not exceed 14 degrees 
angular rotation for manual steering systems, and 30 degrees angular 
rotation for power steering systems.
* * * * *
    (d) Steering system. Universal joints and ball-and-socket joints 
shall not be worn, faulty or repaired by welding. * * * .
* * * * *
[FR Doc. 97-9056 Filed 4-11-97; 8:45 am]
BILLING CODE 4910-22-P