[Federal Register Volume 64, Number 129 (Wednesday, July 7, 1999)]
[Proposed Rules]
[Pages 36657-36664]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-17235]


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DEPARTMENT OF TRANSPORTATION

National Highway Traffic Safety Administration

49 CFR Part 571

[Docket No. 99-5891]
RIN 2127-AH14


Federal Motor Vehicle Safety Standards; Child Restraint Systems

AGENCY: National Highway Traffic Safety Administration (NHTSA), 
Department of Transportation.

ACTION: Request for comments.

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SUMMARY: The agency is issuing this document to obtain information that 
will help NHTSA determine whether Safety Standard No. 213, ``Child 
Restraint Systems,'' should be amended in response to a petition for 
rulemaking from Kathleen Weber of Ann Arbor, Michigan. The petition 
concerns the availability of child booster seats for older children 
(ages about 4 and older) that can be used in older cars whose rear 
seats are equipped with only lap belts instead of both lap and shoulder 
belts. To make it easier for child restraint manufacturers to produce 
child restraints for these children, the petition asks that Standard 
213 be amended such that compliance tests of booster seats may be 
conducted with a top tether attached.
    In the past, many drivers did not attach tethers when they used 
tether-equipped child restraints in vehicles that lack user-ready 
tether anchorages. Given that the vehicles in question lack user-ready 
tether anchorages, the agency seeks comments on the extent to which 
vehicle drivers would attach the booster seat's top tether. The agency 
also seeks comments on the extent to which currently available vests, 
harnesses, and other restraint systems (e.g., shoulder belt retrofits) 
address the problem raised by the petitioner. Comments are requested on 
the feasibility of redesigning boosters such that the restraints can 
meet Standard 213's requirements when attached to the vehicle with only 
a lap belt, and without the use of a tether.

DATES: You should submit your comments early enough to ensure that 
Docket Management receives them not later than September 7, 1999.

ADDRESSES: You should mention the docket number of this document in 
your comments and submit your comments in writing to: Docket 
Management, Room PL-401, 400 Seventh Street, SW, Washington, DC, 20590.
    You may call Docket Management at 202-366-9324. You may visit the 
Docket from 10 a.m. to 5 p.m., Monday through Friday.

FOR FURTHER INFORMATION CONTACT: For non-legal issues, you may call 
Mike Huntley of the NHTSA Office of Crashworthiness Standards, at 202-
366-0029.
    For legal issues, you may call Deirdre Fujita of the NHTSA Office 
of Chief Counsel at 202-366-2992.
    You may send mail to both of these officials at National Highway 
Traffic Safety Administration, 400 Seventh St., SW., Washington, DC., 
20590.

SUPPLEMENTARY INFORMATION:

Table of Contents

I. Background
    a. The booster seats in question became unavailable after 
upgrade to Standard 213
    b. Petitioner seeks to make boosters available by allowing them 
to be tethered in compliance test
    c. The safety concern is that tethers often were not used in 
vehicles lacking a user-ready tether anchorage, even by parents who 
were aware of the importance of attaching the tether
    d. The recent regulation requiring user-ready tether anchorages 
to improve tether use will not apply to vehicles manufactured before 
September 1999
II. Issues
III. Comments
Appendix A--Calspan Study
APPENDIX B-NHTSA TEST PROGRAM

I. Background

    On December 4, 1997, Ms. Kathleen Weber of the University of 
Michigan Child Passenger Protection Research Program, submitted a 
petition for rulemaking to amend Federal Motor Vehicle Safety Standard 
No. 213, ``Child Restraint Systems'' (49 CFR 571.213). The petition, 
which NHTSA granted on January 30, 1998, concerns the manufacture of 
booster seats that can be used by families using pre-1989 model year 
vehicles. These vehicles have only lap belts in rear seating positions.
    a. The Booster Seats in Question Became Unavailable After Upgrade 
to Standard 213
    Booster seats are designed for children who have outgrown a 
convertible or toddler child restraint system. They are generally 
designed for children who are about 4 to 8 years old. There are two 
main types of booster seats currently produced. One type is called a 
``shield booster'' due to use of a shield-like barrier to restrain the 
upper torso of a child in a crash. Shield boosters attach to the 
vehicle by the vehicle's lap belt (Type I belt) or lap belt portion of 
a lap and shoulder belt (Type II belt). The other type of booster is 
called a ``belt-positioning seat,'' which is a booster designed to use 
both portions of a vehicle's Type II belt to restrain the child. A 
belt-positioning seat is not directly attached to the vehicle seat, but 
is held in place by the child's mass and the vehicle's Type II belt, 
which is strapped over the child's lap and torso, just as the Type II 
belt is used to restrain an adult occupant. A belt-positioning seat 
must not be used with a vehicle's lap belt alone, since the seat lacks 
structure or an internal belt to restrain the child's upper torso.
    Shield booster seats, which are capable of being used with only a 
vehicle's lap belt, were available in the past, but became unavailable 
for children weighing over 18 kilograms (kg) (approximately 40 pounds, 
lb) subsequent to an upgrade that NHTSA made to the standard pursuant 
to the Intermodal Surface Transportation Efficiency Act (``ISTEA'') of 
1991 (Pub. L. 102-240). That Act directed NHTSA to initiate rulemaking 
on a number of safety matters, including child booster seat safety 
(section 250). The legislative

[[Page 36658]]

history for the directive indicated that its impetus was a study 
1 that found that shield booster seats then manufactured 
could not adequately restrain test dummies representative of the 
children for whom manufacturers typically recommended for the seats. In 
the study, the boosters could not adequately restrain a 22 kg (48 lb) 
test dummy (representing a 6-year-old) when dynamically tested under 
Standard 213. The boosters were ineffective at limiting head excursions 
to within the requirements of Standard 213, and two of the boosters 
failed structurally. The boosters also failed to prevent the ejection 
of a 9 kg (20 lb) test dummy (representing a 9-month-old child) in the 
dynamic test. These phenomena were observed notwithstanding the 
recommendation of some booster seat manufacturers that their seats were 
suitable for children weighing from 9 up to 32 kg (20 up to 70 
lb).2
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    \1\  Calspan Corporation (DOT HS 807 297, May 1988). A detailed 
discussion of this study can be found in Appendix A to today's 
document.
    \2\  Because at that time only a 3-year-old dummy was used in 
Standard 213's compliance test, the boosters could meet the standard 
when tested with that dummy and were thus certified as complying 
with the standard.
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    In response to this study and to the ISTEA directive, NHTSA amended 
Standard 213 to permit the manufacture of belt-positioning seats, which 
were considered to be a new, superior type of booster seat (59 FR 
37167, July 21, 1994). Belt-positioning boosters were believed to be 
better able than shield boosters at accommodating a wider range of 
child sizes. These boosters have since replaced shield boosters in the 
marketplace, as many commenters to the rulemaking, including the 
petitioner for this document, Kathleen Weber, had hoped they would. 
NHTSA also incorporated the 6-year-old and 9-month-old dummies into the 
standard's compliance test protocols, to ensure a more thorough 
evaluation of the ability of a child restraint to adequately restrain 
children recommended for the restraint, as compared to testing done 
with only the 3-year-old dummy. Beginning in September 1996, any child 
restraint recommended for children weighing over 18 kg (40 lb) must be 
able to comply with the standard when tested with the 6-year-old child 
dummy (60 FR 35126, July 6, 1995; 60 FR 63651, December 12, 1995).
    Comments from manufacturers and others on the proposal to use the 
6-year-old dummy in compliance tests did not indicate that shield 
boosters manufactured at the time of the rulemaking could not comply. 
To the extent there were any shield boosters that could not pass the 
standard's requirements with the 6-year-old dummy, NHTSA anticipated 
that manufacturers might (1) design their seats to achieve compliance 
(such as by raising the height of the shield relative to the child's 
torso), (2) relabel shield boosters as being suitable for children 
weighing less than 18 kg (and thus avoid testing with the 6-year-old 
dummy), or (3) replace production of shield boosters with belt-
positioning boosters. While the latter two responses to the final rule 
have occurred, manufacturers have not redesigned shield boosters to 
pass Standard 213 with the 6-year-old dummy. Thus, the shield boosters 
manufactured today are not recommended for use by children over 18 kg 
(40 lb).

b. Petitioner Seeks To Make Boosters Available by Allowing Them To Be 
Tethered in Compliance Test

    Petitioner does not want to see the renewed sale of shield booster 
seats, because she does not believe the restraints provide adequate 
upper torso restraint. Instead, the petitioner suggests that Standard 
213 be amended to allow--

    ``hybrid'' toddler/booster restraints (forward facing with 
internal harness/high-back belt-positioning booster) to be used by a 
(20 kg) 45 lb child in the toddler mode with its internal harness 
and installed with a lap belt and top tether strap.

    The petitioner is referring to child restraints that can be used 
with a Type I (lap) belt and with a Type II (lap/shoulder) belt. An 
example of such a seat is Century's Breverra booster car seat, which is 
recommended for children 14 to 27 kg (30 to 60 lb). The Breverra has a 
removable 5-point harness system. When used with children weighing up 
to 18 kg (40 lb), the Breverra is used with the 5-point harness, and 
the restraint is secured to the vehicle seat by either a Type I or Type 
II belt. (In vehicles equipped with Type II belt systems, a locking 
clip may be required for proper installation of the restraint.) This 
configuration (using the restraint system with children weighing up to 
18 kg (40 lb), and restraining them with the internal 5-point harness) 
is what the petitioner refers to as the ``toddler mode.'' The Breverra 
is also designed for use as a belt-positioning seat with children 14 to 
27 kg (30 to 60 lb). Parents are instructed to remove the 5-point 
harness from the booster seat, and to use the car's Type II belt to 
restrain the child. Because seats such as the Breverra are designed for 
use both as a ``toddler seat'' and as a ``belt-positioning booster 
seat,'' petitioner refers to them as ``hybrid'' restraints.
    Petitioner seeks to permit hybrid restraints to be certified as 
meeting the standard when recommended for children up to 20 kg (45 lb) 
in the toddler mode (using the 5-point harness, attached to the vehicle 
by lap belt). Currently, restraints recommended for children up to 20 
kg are tested with the 6-year-old dummy. Hybrid restraints cannot meet 
the head excursion limit, untethered, when tested with the 6-year-old 
dummy in the toddler mode (using the 5-point harness). Presumably, they 
can meet it tethered.
    A number of parties have written to NHTSA in support of the 
petition, including Safe Ride News and SafetyBeltSafe (both reiterated 
the views of the petitioner). The American Academy of Pediatrics (AAP) 
said that a high-back booster would help in physically restraining 
young toddlers who can easily escape from Type II belts. The National 
Transportation Safety Board (NTSB) expressed concern that the lack of 
child restraints for older children complicates efforts to encourage 
states to enact legislation to require children to ride in the back 
seat. However, NTSB did not support measures that required use of a 
tether or retrofitting a vehicle with a rear seat shoulder belt (these 
approaches, and others, are discussed further below). NTSB hoped that 
NHTSA will ``work with the child restraint manufacturers to expedite 
efforts to provide child restraint systems for children who have 
outgrown their convertible restraint systems to be used with lap-only 
belts.''

c. The Safety Concern Is That Tethers Often Were Not Used in Vehicles 
Lacking a User-Ready Tether Anchorage, Even by Parents Who Were Aware 
of the Importance of Attaching the Tether

    Tether use in vehicles not originally equipped with tether 
anchorages has been very low in this country. Because of the low use 
rate for tethers, NHTSA amended Standard 213 in 1986 to require 
tethered child restraints to pass the 48 kph (30 mph) test without 
attaching a tether (51 FR 5335). NHTSA amended the standard because 
surveys that had been conducted for the agency consistently showed that 
tethered restraints were used in those vehicles without the tether 
strap attached more than 80 percent of the time. Seventy-eight (78) 
percent of persons not using the tether strap knew that its use was 
necessary for their child's protection, but still did not attach the 
tether. Given the low level of tether strap use in vehicles lacking a 
user-ready tether anchorage and the high level of awareness that the 
strap must be used,

[[Page 36659]]

the agency did not believe that a tether strap could continue to be 
permitted as a device necessary for the adequate protection of 
children.
    Child restraint harnesses and vests were not affected by the 
rulemaking. This is because the potential for misuse of harnesses and 
vests seemed to be significantly less than for tethered child seats. 
With child harnesses and vests, it would be obvious to parents that if 
the tether were not attached, the child would be completely 
unrestrained in a crash. NHTSA also noted that its data on the non-use 
and misuse of tethers did not study the extent to which the tethers are 
improperly used on harnesses and vests. To date, harnesses and vests 
are tested with the tether strap secured.

d. The Recent Regulation Requiring User-Ready Tether Anchorages to 
Improve Tether Use Will Not Apply to Vehicles Manufactured Before 
September 1999

    To promote higher tether use, NHTSA has recently issued a final 
rule that requires vehicle manufacturers to install factory-installed, 
user-ready tether anchorages (with hardware) in new vehicles, beginning 
September 1, 1999. 3 We believe, as do Canada and Australia, 
that tether use improves when factory installed tether anchorages are 
provided on vehicles as standard equipment. However, the requirement 
for user-ready tether anchorages applies to vehicles manufactured on or 
after September 1, 1999, and will not apply to the vehicles that are 
the subject of the petition (older vehicles with only lap belts in rear 
seating positions).
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    \3\ The rule also amended Standard 213 to add a 720 millimeter 
(mm) (28 inch) head excursion limit for forward-facing child 
restraints, which manufacturers may meet by attaching a tether. The 
existing 813 mm (32 inch) head excursion requirement will also have 
to be met, with the tether unattached, to maximize head protection 
even when the tether is not attached by a consumer.
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II. Issues

    The agency seeks comments that will help it to assess whether NHTSA 
should amend Standard 213 to permit booster seats, and possibly other 
child restraint systems, to be tethered in determining compliance with 
the head excursion requirements, and possibly with other requirements 
as well.
    NHTSA notes that the circumstances that gave rise to the petition 
are diminishing. Vehicles manufactured in 1989 and after are required 
to have Type II (lap and shoulder) belts installed in rear outboard 
seating positions, enabling the use of belt-positioning booster seats, 
with the Type II belts, for children weighing more than 18 kg. Pre-1989 
vehicles are at the root of the issue, because they typically have no 
Type II (lap and shoulder) belts in the rear seats. However, these 
vehicles are steadily declining in number and eventually will be 
replaced by vehicles with rear seat Type II belts.
    This document sets forth below a number of requests for comments 
and data. For easy reference, the requests are numbered consecutively. 
In providing a comment on a particular matter or in responding to a 
particular question, commenters should provide any relevant factual 
information to support their conclusions, including but not limited to 
cost and statistical data, and the source of such information.

Question 1. How Likely Are Tethers To Be Used in Vehicles That Lack 
User-Ready Tether Anchorages?

    Tether use in vehicles not originally equipped with tether 
anchorages has been very low in this country. Are there data that show 
that tether use in vehicles not originally equipped with a tether 
anchorage will be greater than it has been in the past?
    The petitioner's approach would delete the head excursion 
requirement when the seat is tested untethered with the 6-year-old 
dummy, i.e., in the manner that data show the seat is likely to be used 
in a vehicle that did not have an originally-installed tether 
anchorage. NHTSA conducted testing at our Vehicle Research and Test 
Center (VRTC) in March 1998, to evaluate the performance of various 
types of child restraints in limiting the amount of head excursion of 
the 6-year-old dummy. The test program is discussed in Appendix B, and 
a test report has been placed in the general reference docket for 
Standard 213, NHTSA-99-5426. Our testing showed that untethered seats 
were unable to meet the head excursion requirement. The seats generally 
allowed between 795 and 851 mm (31.29 and 33.52 inches) of head 
excursion. Nonuse of the tether will affect the possible advantages of 
petitioner's suggested change.

Question 2: Is a Child Better Off in an Untethered Booster or Seated 
Directly on the Vehicle Seat and Restrained by a Lap Belt? Are There 
Alternative Approaches?

    NHTSA's March 1998 testing program showed head excursions of the 6-
year-old dummy of up to 851 mm (33.52 inches) for untethered 
restraints. Data are unavailable for head excursions for dummies 
restrained only by a lap belt.
    A preliminary study conducted by NHTSA, based on data from the 
Fatality Analysis Reporting System (FARS) from 1988 through the first 6 
months of 1997, compared the experience of unrestrained rear seat 
occupants to some children using a lap belt only and to other children 
using both lap and shoulder belts. The study found that for children 
ages 5-14, use of a lap belt only while seated in a back outboard seat 
of a car is 38 percent effective in reducing fatalities and use of a 
back seat lap/shoulder belt is 52 percent effective in reducing 
fatalities. The study shows that these children appear to derive the 
greatest incremental benefit from using back seat lap/shoulder belts 
rather than just a lap belt when compared to the other age and sex 
groups evaluated in the study. In comparison, NHTSA estimates that 
child restraints are potentially 71 percent effective in reducing the 
likelihood of death.4
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    \4\ Kahane, Charles J. (1986), An Evaluation of the 
Effectiveness and Benefits of Safety Seats, U.S. Department of 
Transportation, National Highway Traffic Safety Administration, DOT 
HS 806 889, p. 305. The agency believes that this figure remains 
valid.
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    The same study also showed that, based on FARS and Multiple Cause 
of Death (MCOD) data from 1988-1994, children ages 5-14 do not have an 
increased risk of abdominal injuries compared to occupants in other age 
groups. Lap belted and lap/shoulder belted children have abdominal 
injury rates slightly higher than unrestrained children in frontal 
crashes (12 and 15 per 100, respectively as compared to 9 per 100 for 
unrestrained). These rates are at or below the injury rate of lap 
belted and lap/shoulder belted occupants of all ages in frontal 
crashes. However, the same data indicate that the head injury rate for 
children ages 5-14 in the back seat in frontal crashes restrained by a 
lap belt only is double that (50 versus 25 per 100) of those children 
restrained with a lap and shoulder belt (and thus provided with upper 
torso protection similar to what could be expected through the use of 
child restraint systems).
    Head excursions beyond that limited by Standard 213 reduce the 
level of performance now required by 213. However, some believe that 
using a lap belt without an upper torso restraint could result in 
``seat belt syndrome,'' which refers to bruising across the abdomen, 
internal injuries and lower spine fractures which, allegedly, are 
caused mainly by a lap belt that is used incorrectly or that moves off 
the child's pelvis during a crash. Are children restrained only by a 
lap belt experiencing seat belt syndrome? Should we reduce the 
protection required in the standard against head

[[Page 36660]]

impacts to broaden the protection against seat belt syndrome?
    If there were no head excursion limit when a booster seat is tested 
untethered with the 6-year-old dummy, this would seem to require no 
more of booster seats than what is expected when the dummy is seated 
directly on the vehicle seat and restrained by just a lap belt. An 
alternative approach could be to increase Standard 213's head excursion 
limit from 813 mm (32 inches) to 838 mm (34 inches) when testing a 
booster seat untethered with the 6-year-old dummy. Under that approach, 
there would be a limit to head excursion, even in the untethered 
condition. Comments are requested on this approach.

Question 3: Should the Test That Evaluates Child Restraint Performance 
Without Attaching the Tether Be Deleted for All Restraints, Not Just 
Hybrid Toddler/Booster Restraints? Should the Test Be Deleted When 
Testing With Dummies Other Than the 6-Year-Old?

    If a tether were permitted to be attached when testing with the 6-
year-old dummy, should tethers be attached with testing with the 3-
year-old as well, such as when testing convertible child restraints 
(which are usually recommended for children from birth to 18 kg (40 
lb))? The agency believes that deleting the test for these other 
restraints and in tests with other dummies is inadvisable at this time, 
in the absence of data indicating whether tethers would be properly 
used. However, what reasons would justify distinguishing between tether 
use rates among hybrid boosters and other types of child seats or 
otherwise justify why a tether could be attached for some restraints 
and not for others?

Question 4: Why Are Shield Boosters No Longer Manufactured for Children 
Weighing over 18 kg (40 lb)?

    In the March 1998 test program at VRTC, the agency tested four 
currently available types of shield booster seats with the 6-year-old 
dummy. Two units of one of these shield boosters were tested, and in 
each instance, they appeared to meet all performance criteria of 
Standard 213, including the head injury criterion (HIC), chest 
acceleration limits, and the head and knee excursion limits. Yet, the 
booster was recommended for use by children only up to 18 kg (40 lb). 
NHTSA later tested 3 other available shield-type booster seats using 
the 6-year-old dummy and found that each exceeded the 813 mm (32 inch) 
head excursion limit of Standard 213.
    NHTSA requests information, particularly from child restraint 
manufacturers, concerning the reasons why shield boosters are no longer 
marketed for children weighing more than 18 kg (40 lb), especially with 
respect to those boosters that appear to meet all performance criteria 
of Standard 213. Were some manufacturers unable to certify that the 
seats would meet Standard 213's requirements when tested with the 6-
year-old dummy? If they did so conclude, was it solely the head 
excursion requirement, or other requirements as well? Were there test 
failures, and if so, what were the margins of failure? Can shield 
boosters be redesigned to achieve compliance with the standard? Why 
have manufacturers not redesigned these boosters to achieve compliance?

Question 5: What Is the Feasibility of Redesigning Hybrid/Toddler 
Booster Restraints Such That the Restraint Can Be Certified for Use 
With Older Children, Without the Use of a Tether?

    NTSB hoped that NHTSA will ``work with the child restraint 
manufacturers to expedite efforts to provide child restraint systems 
for children who have outgrown their convertible restraint systems to 
be used with lap-only belts.'' NHTSA requests comments on the 
feasibility of designing a hybrid booster seat such that the booster 
can meet the current requirements of Standard 213 in the ``toddler 
mode'' when tested with the 6-year-old dummy, and when attached to the 
standard seat assembly with just a lap belt and without a tether.

Question 6: Is the Suggested Amendment Warranted When There Are 
Products Now Available for Older Children That May Perform Better Than 
a Tethered Seat at Limiting Head Excursion?

    E-Z-On Products, Inc., manufactures vest and harness restraint 
systems for use with a lap belt and tether. Vests and harnesses are 
``child restraint systems'' under Standard 213 and are certified as 
meeting all requirements of the standard.
    The vest and harness systems employ a top tether to meet Standard 
213's requirements. As explained above, Standard 213 permits a tether 
on a vest or harness system (both are referred to as ``harnesses'' in 
the standard) to be attached in the 48 km/h (30 mph) test, but does not 
allow a tether to be attached on a conventional child restraint system 
(such as a convertible child restraint or a high-back booster, such as 
the Breverra). The reason for the different treatment is because it is 
more obvious that a tether needs to be attached with vests and 
harnesses than it is with conventional child seats. If a tether were 
not used for a vest or harness, it would be clear to the parent that 
the child's upper torso would have no restraint.
    The E-Z-On Vest is designed to slip over the child, with a back 
zipper closure. The vest is custom-made, using the child's waist 
measurement. E-Z-On's Universal Harness is in the shape of an upside 
down ``Y.'' There are two straps at the bottom of the upside down ``Y'' 
with loops at each end, that the lap belt is threaded through. The 
upper part of the upside down ``Y'' has a tether hook which attaches to 
the vehicle's tether anchor. E-Z-On has informed NHTSA that its vest 
and harness systems are readily available through its distributors. A 
vest or harness can be shipped to the consumer within 2 weeks. The 
price of the vest is approximately $73 to $95, a cost comparable to 
that of convertible seats. The harness costs approximately $45.
    NHTSA's March 1998 test program at VRTC evaluated the performance 
of various types of child restraints, including vests and harnesses, 
hybrid boosters and convertible restraints, in limiting the amount of 
head excursion of the 6-year-old dummy (see Appendix B). In brief, the 
tethered vest and harness performed much better than the tethered 
hybrid booster or tethered convertible restraint at limiting head 
excursion. Test data for the tethered restraints were as follows:

                         Table 1.--Summary of Sled Test Results for Tethered Restraints
----------------------------------------------------------------------------------------------------------------
                                                                      Head         Knee
        Restraint configuration             HIC       3 ms chest   excursion    excursion         Test No.
                                                       clip (G)       (mm)         (mm)
----------------------------------------------------------------------------------------------------------------
FMVSS No. 213 limit...................         1000           60          813          914
Century Breverra Contour/5-pt. Harness          332         38.9       760.22       904.49  UMP03
 Lap Belt w/Top Tether.
Century Breverra Contour/5-pt. Harness          307         40.5       718.82       880.62  UMP05
 Lap Belt w/Top Tether.
E-Z ON 86-Y Harness Lap Belt w/Top              463         52.5       495.30       540.26  UMP07
 Tether.

[[Page 36661]]

 
E-Z ON 103Z Vest Lap Belt w/Top Tether          702         59.3       558.29       635.76  UMP08
E-Z ON 86-Y Harness Lap Belt w/Top              461         52.9       473.71       539.75  UMP09
 Tether.
Britax Roundabout Lap Belt w/Top                270         42.3       622.55       798.83  UMP11
 Tether.
Britax Roundabout Lap Belt w/Top                303         43.4       574.04       736.09  UMP13
 Tether.
Britax Elite Lap Belt w/Top Tether....          554         51.2       640.08       782.32  UMP15
Britax Elite Lap Belt w/Top Tether....          614         58.9       580.39       719.84  UMP17
----------------------------------------------------------------------------------------------------------------

    Based on this test program, NHTSA believes that vests and harnesses 
could address petitioner's concerns and those of the other parties. The 
E-Z-On Vest, with a back zipper closure, could address AAP's desire for 
a product that can restrain young toddlers who have reached 18 kg (40 
lb), but who are too immature behaviorally to use Type II belts. There 
may be perceived drawbacks to vests and harnesses. A vest may not be as 
convenient as a hybrid booster. The vest wraps around the child's torso 
and has to be unclipped from the tether mounting strap to be placed on 
a child. Also, vests and harnesses do not ``look like'' traditional 
child restraint systems so they might not be as readily accepted by 
some consumers as a tethered hybrid seat might be. Yet, owners of older 
vehicles who are seeking any product to fix a perceived problem 
concerning their youngsters may be more motivated to accept a harness 
than consumers generally.
    NTSB did not support measures that required use of a tether, given 
the high non-use rates of tethers in this country. Yet, the likelihood 
that parents will attach the tether on a harness could be higher than 
that for conventional child seats, given that it would be more obvious 
to a parent that the tether has to be attached on a vest or harnesses 
than on a restraint such as a hybrid booster, which would be designed 
to be used both with and without a tether, depending on the size of the 
child occupant.
    While the hybrid booster might be preferred by some consumers over 
a vest or harness because of the expectations of consumers as to what a 
child restraint system ought to look like, an untethered hybrid booster 
does not restrict head excursion as well as a tethered vest or harness.

Question 7: Would Adoption of the Suggested Amendment Inappropriately 
Encourage Some Parents To Position Restraints in the Center Rear 
Seating Position?

    Petitioner only addressed the need of consumers with pre-1989 cars, 
but adoption of the suggested amendment could also affect the 
preference of parents who wish to install a booster seat in the center 
rear position. The center rear position typically has only a Type I 
(lap) belt, not a Type II (lap and shoulder) belt system. Some of these 
parents may welcome having booster seats that can be used in the center 
rear seat with only a Type I belt. However, optimal performance of the 
restraint is dependent on attachment of the tether. An untethered seat 
in the center rear seat is not likely to perform as effectively as an 
untethered belt-positioning booster used at the outboard seating 
position with a Type II belt system. Would the suggested amendment 
encourage consumers to move belt-positioning seats from outboard 
seating positions to the center rear seat? How likely will consumers 
attach a tether 5 when using the seat with children weighing 
more than 18 kg (40 lb)?
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    \5\ Our March 1999 final rule excludes belt-positioning seats 
from the head excursion limit that requires a tether on the child 
restraint. Thus, a belt-positioning seat that is not also a hybrid 
toddler seat might not even have a tether.
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Question 8: What Is the Feasibility of Retrofitting a Rear Seat 
Shoulder Belt in Pre-1989 Vehicles?

    Retrofitting vehicles with a rear seat shoulder belt is another 
option. While this approach is more expensive than installing a tether 
anchorage (assuming there are structural elements for the tether 
anchorage already in the vehicle), a shoulder belt can benefit children 
who have completely outgrown a child restraint, and can also benefit 
adults, seated in the rear. Many vehicle manufacturers offer shoulder 
belt kits for rear seating positions, although availability and cost of 
these kits vary widely. Because of the long term benefits associated 
with this option as described above, we have suggested this approach to 
many consumers who have contacted the agency in search of alternatives. 
The majority of these consumers were unaware that vehicle manufacturers 
offered such retrofit kits, and were generally very receptive to having 
the retrofit kits installed in their vehicles. A minority expressed 
reservations given the disproportionate cost of the retrofit kit parts 
and installation when compared to the limited value of their older 
vehicle.

III. Comments

How Do I Prepare and Submit Comments?

    Your comments must be written and in English. To ensure that your 
comments are correctly filed in the Docket, please include the docket 
number of this document in your comments.
    Your comments must not be more than 15 pages long. (49 CFR 553.21). 
We established this limit to encourage you to write your primary 
comments in a concise fashion. However, you may attach necessary 
additional documents to your comments. There is no limit on the length 
of the attachments.
    Please submit two copies of your comments, including the 
attachments, to Docket Management at the address given above under 
ADDRESSES.

How Can I Be Sure That My Comments Were Received?

    If you wish Docket Management to notify you upon its receipt of 
your comments, enclose a self-addressed, stamped postcard in the 
envelope containing your comments. Upon receiving your comments, Docket 
Management will return the postcard by mail.

How Do I Submit Confidential Business Information?

    If you wish to submit any information under a claim of 
confidentiality, you should submit three copies of your complete 
submission, including the information you claim to be confidential

[[Page 36662]]

business information, to the Chief Counsel, NHTSA, at the address given 
above under FOR FURTHER INFORMATION CONTACT. In addition, you should 
submit two copies, from which you have deleted the claimed confidential 
business information, to Docket Management at the address given above 
under ADDRESSES. When you send a comment containing information claimed 
to be confidential business information, you should include a cover 
letter setting forth the information specified in our confidential 
business information regulation. (49 CFR part 512.)

Will the Agency Consider Late Comments?

    We will consider all comments that Docket Management receives 
before the close of business on the comment closing date indicated 
above under DATES. To the extent possible, we will also consider 
comments that Docket Management receives after that date.

How Can I Read the Comments Submitted by Other People?

    You may read the comments received by Docket Management at the 
address given above under ADDRESSES. The hours of the Docket are 
indicated above in the same location.
    You may also see the comments on the Internet. To read the comments 
on the Internet, take the following steps:
    (2) Go to the Docket Management System (DMS) Web page of the 
Department of Transportation (http://dms.dot.gov/).
    (3) On that page, click on ``search.''
    (4) On the next page (http://dms.dot.gov/search/), type in the 
four-digit docket number shown at the beginning of this document. 
Example: If the docket number were ``NHTSA-1999-1234,'' you would type 
``1234.'' After typing the docket number, click on ``search.''
    (5) On the next page, which contains docket summary information for 
the docket you selected, click on the desired comments.
    You may download the comments. However, since the comments are 
imaged documents, instead of word processing documents, the downloaded 
comments are not word searchable.
    Please note that even after the comment closing date, we will 
continue to file relevant information in the Docket as it becomes 
available. Further, some people may submit late comments. Accordingly, 
we recommend that you periodically check the Docket for new material.

Appendix A--Calspan Study

    Both of the rules that amended Standard 213 to permit the 
manufacture of belt-positioning booster seats and to adopt new test 
dummies into the standard for compliance tests responded to sections 
2500-2509 of the Intermodal Surface Transportation Efficiency Act of 
1991 (Pub. L. 102-240), which directed NHTSA to initiate rulemaking on 
a number of safety matters, including child booster seat safety 
(Sec. 2503). The legislative history for the directive indicated that 
the directive evolved in large part from the findings of a study 
entitled, ``Evaluation of the Performance of Child Restraint Systems,'' 
performed for NHTSA by the Calspan Corporation (DOT HS 807 297, May 
1988). Congress believed that the study showed that some booster seats 
``may not restrain adequately a child in a crash . . . .'' Senate 
Committee on Commerce, Science, and Transportation, S. Rep. No. 83, 
102d Cong., 1st Sess. 6, 18 (1991). Concerns about shield boosters had 
arisen from the recommendations by child restraint manufacturers about 
which children could appropriately use a particular booster. Particular 
designs or models of boosters were typically recommended for a broad 
range of children, often for children weighing from 9 to 32 kg (20 to 
70 lb). At the time of the study, such a child restraint was tested for 
compliance with Standard 213 with just the 3-year-old (15 kg) (33 
pound) dummy. So tested, these restraints met Standard 213. However, 
there were questions whether the boosters could provide adequate 
protection for children at the extremes of the weight ranges that had 
been recommended by the manufacturer as being suitable for the 
restraint, i.e., those ranging from nine-month-old infants (average 
weight 9 kg) to 6-year-old (22 kg) and older children.
    In the Calspan program, the nine-month-old infant and the 6-
year-old child dummies were used in addition to the 3-year-old 
dummy. The Calspan research program tested all 11 models of booster 
seats that were on the market during the summer of 1987. In tests 
with the 6-year-old dummy, Standard 213's 813 mm (32 inch) head 
excursion limit was exceeded by 10 out of 11 booster seat models, 
with measurements in the range from 813 to 899 mm (32.0 to 35.4 
inches). One model ejected the dummy.
    Following the Calspan study, NHTSA conducted additional research 
on boosters. Nine booster seats were tested with the three dummies 
used in the Calspan study. The seats met the performance measures of 
Standard 213 when tested with the 3-year-old dummy. However, 7 of 9 
allowed excessive head excursions with the 6-year-old dummy, and two 
of the seats also had structural failures with the dummy. 
``Evaluation of Booster Seat Suitability for Children of Different 
Ages and Comparison of Standard and Modified SA103C and SA106C Child 
Dummies,'' VRTC-89-0074, February 1990.

Appendix B--NHTSA Test Program

    NHTSA developed and conducted a test program at VRTC from March 
16-20, 1998, to evaluate the performance of various types of child 
restraints in restricting the amount of head excursion of the 6-
year-old dummy. In developing this test program, NHTSA asked child 
restraint manufacturers and the NTSB for suggestions as to which 
approaches and products should be evaluated. One objective of this 
test program was to obtain baseline information on the dynamic 
performance of a ``typical'' shield-type booster seat, tested with 
the 6-year-old dummy while secured to the vehicle seat by a lap belt 
only. It is the presumed inability of this type of seat to meet the 
813 mm (32 inch) head excursion requirement of Standard 213 that has 
apparently resulted in child restraint manufacturers limiting these 
restraints to use for children weighing no more than 18 kg (40 lb). 
Pre-test discussions with restraint manufacturers confirmed that 
Standard 213's head injury criterion (HIC), chest acceleration, and 
knee excursion parameters did not pose concerns when testing this 
type of restraint with the 6-year-old dummy. Rather, because of the 
increase in height and weight of the 6-year-old dummy as compared to 
the 3-year-old dummy--1168 versus 965 mm standing height (46 versus 
38 inches), and 22 versus 15 kg in weight (48 versus 33 lb)--the 
shield portion of the restraint apparently does not provide adequate 
upper torso restraint to limit the head excursion within acceptable 
limits when subjected to Standard 213's dynamic test. NHTSA chose 
the Cosco Grand Explorer as a representative shield-type booster for 
this baseline test.
    The test program also evaluated a representative high-back belt-
positioning booster seat, utilizing its internal 5-point harness, 
secured to the vehicle seat by a lap belt and a top tether. This 
represents the specific configuration recommended in the Weber 
petition. NHTSA chose the Century Breverra, which comes with an 
optional top tether, as a representative seat for the test program.
    NHTSA also tested a few convertible seats. Pre-test 
conversations with restraint manufacturers indicated that there may 
be some convertible restraints that are equipped with tethers that 
may also perform adequately when attached to the vehicle seat with a 
lap belt only, when restraining the 6-year-old dummy. Not all 
convertibles are equipped with a top tether strap, and not all 
convertible seats will be able to accommodate the 6-year-old dummy. 
Britax Child Safety, Inc. indicated that they currently manufacture 
two convertible restraints, the ``Roundabout'' which comes with a 
standard top tether, and the ``Elite'' which comes with an optional 
top tether attachment, which they felt would perform satisfactorily 
in a crash test with the 6-year-old dummy with the restraint secured 
to the vehicle seat by a lap belt and top tether. Accordingly, NHTSA 
included each of these

[[Page 36663]]

convertible restraints in the subject test program.
    Currently, the only commercially available products that are 
marketed specifically for children weighing over 18 kg (40 lb) and 
secured with a lap belt only are the Y-harness and vest systems 
produced by E-Z On Products. Both of these systems require the use 
of a top tether. The Y-harness system consists of two shoulder 
straps which extend from the top tether anchorage, with looped ends 
to allow the vehicle lap belt to be routed through and fastened over 
the pelvic area. Similarly, the tether strap is attached to the vest 
system by attaching the two snap hooks on end of the tether strap to 
rings located on the shoulders of the vest, and the vehicle lap belt 
is threaded through the web loops on the bottom of each side of the 
vest. Both the Y-harness and the vest systems were included in the 
test program for evaluation.
    The dynamic sled tests were conducted at NHTSA's Vehicle 
Research and Test Center, (VRTC), and were based on the test 
conditions and procedures prescribed in S6 of Standard No. 213. 
However, it must be emphasized that this test program was intended 
for research only and did not precisely replicate compliance 
testing. The VRTC tests evaluated the ability of the restraints at 
limiting head excursion, HIC, chest acceleration, and knee 
excursion. The test conditions were fixed throughout the sled test 
series, with the only variable being the particular restraint being 
tested and its attachment method (i.e. tethered or untethered). With 
the exception of the baseline test utilizing the Cosco Grand 
Explorer shield booster seat, each restraint was tested in each 
attachment configuration on two separate sled runs to enhance the 
repeatability of the test results. Two Cosco Grand Explorer 
restraints were tested, but on the same sled run versus separate 
sled runs as with the other restraints.
    All tests were conducted using the 6-year-old dummy, and each of 
the restraints--whether tethered or untethered--was attached to the 
vehicle test seat using a lap belt only. Standard 213's limits are 
as follows: HIC--1000; chest acceleration--60g; head excursion--813 
mm (32 inches); and knee excursion--914 mm (36 inches). The full 
test results are provided in Table 2. It is important to note that 
in each of the tests conducted, values for both the HIC and chest 
acceleration parameters were typically significantly below the 
established limits prescribed in Standard 213 and that none exceeded 
the maximum allowable limits.

                            Table 2.--Summary of Sled Test Results for All Restraints
----------------------------------------------------------------------------------------------------------------
                                                                    Head          Knee
      Restraint configuration            HIC       3 ms chest     excursion     excursion         Test No.
                                                    clip (G)        (mm)          (mm)
----------------------------------------------------------------------------------------------------------------
FMVSS No. 213 limit................         1000          60          813           914
Cosco Grand Explorer Lap Belt w/Sm.          424          32.9        697.74        614.17  UMP01
 Shield.
Cosco Grand Explorer Lap Belt w/Sm.          417          32.2        748.79        660.15  UMP02
 Shield.
Century Breverra Contour/5-pt.               332          38.9        760.02        904.49  UMP03
 Harness Lap Belt w/ Top Tether.
Century Breverra Contour/5-pt.               273          30.8        851.41        925.83  UMP04
 Harness Lap Belt; No Top Tether.
Century Breverra Contour/5-pt.               307          40.5        718.82        880.62  UMP05
 Harness Lap Belt w/ Top Tether.
Century Breverra Contour/5-pt.               243          50.2         NA            NA     UMP06
 Harness Lap Belt; No Top Tether *.
E-Z ON 86-Y Harness Lap Belt w/Top           463          52.5        495.30        540.26  UMP07
 Tether.
E-Z ON 103Z Vest Lap Belt w/Top              702          59.3        558.29        635.76  UMP08
 Tether.
E-Z ON 86-Y Harness Lap Belt w/Top           461          52.9        473.71        539.75  UMP09
 Tether.
E-Z ON 103Z Vest Lap Belt w/Adj.             315          35.9        713.23        597.92  UMP10
 CAM-Wrap.
Britax Roundabout Lap Belt w/Top             270          42.3        622.55        798.83  UMP11
 Tether.
Britax Roundabout Lap Belt; No Top           477          39.3        810.26        895.60  UMP12
 Tether.
Britax Roundabout Lap Belt w/Top             303          43.4        574.0         736.09  UMP13
 Tether.
Britax Roundabout Lap Belt; No Top           425          36.1        794.77        864.36  UMP14
 Tether.
Britax Elite Lap Belt w/Top Tether.          554          51.2        640.08        782.32  UMP15
Britax Elite Lap Belt; No Top                377          39.2        820.17        867.66  UMP16
 Tether.
Britax Elite Lap Belt w/Top Tether.          614          58.9        580.39        719.84  UMP17
Britax Elite Lap Belt; No Top                377          43.1        821.69        878.08  UMP18
 Tether.
Century Breverra Contour/5-pt.               299          31.2        843.79        917.96  UMP19 (Repeat of
 Harness Lap Belt; No Top Tether                                                             UMP06)
 (Repeat of UMP06).
----------------------------------------------------------------------------------------------------------------
* HIC based on head contact w/CRS as dummy slipped out of failed 5-pt. harness.

    While NHTSA anticipated that shield-type boosters could not meet 
the 32-inch head excursion limit of the standard when tested with 
the 6-year-old dummy, test results showed that when tested in this 
configuration, the Cosco Grand Explorer shield booster seats used 
for the baseline testing satisfactorily limited head excursion to 
under 762 mm (30 inches) in both instances. In addition, knee 
excursion was measured to be 254 to 279 mm (10-11 inches) below the 
914 mm (36 inch) limit. These test results are in direct contrast 
with the Calspan and VRTC studies (see Appendix A, supra) conducted 
in support of NHTSA's ISTEA rulemakings on booster seats.
    Following conduct of the baseline test with the shield-type 
booster seat, the agency tested the hybrid boosters and the 
convertible seats both with and without the top tether strap. In the 
tethered configuration, head excursion was measured to be below 762 
mm (30 inches), and knee excursion was measured to be below the 914 
mm (36 inch) limit (although only marginally so in one instance 
(904.49 mm) (35.61 inches)). However, in each of the test runs 
conducted using the untethered configuration, head and knee 
excursions beyond the respective 813 and 914 mm (32 and 36 inch) 
limits were measured, with marginal reductions in both the HIC and 
chest acceleration parameters. It should be noted that a total of 
three test runs was conducted using the untethered configuration, as 
the test dummy slipped out of the child restraint during the second 
test run due to a failure of the 5-point harness, voiding the 
measurement of head and knee excursion. Interestingly, a comparison 
between the untethered shield-type booster used in the baseline 
testing and the tethered hybrid booster (forward facing with 
internal harness/high-back belt-positioning booster) indicates that 
the untethered shield booster performs marginally better (on 
average) with respect to limiting head excursion and significantly 
better with respect to limiting knee excursion than the hybrid 
booster.
    Two convertible restraints were evaluated in the same manner, 
first with a top tether strap attached and then without. In the 
tethered configuration, the Britax Roundabout limited head excursion 
to 622.3 and 574.04 mm (24.5 and 22.6 inches) in the two tests 
performed, well below the 813 mm (32 inch) limit prescribed in the 
standard and also well below the results observed in the baseline 
test with the shield-type booster. Knee excursion measurements were 
also well below the established limit. However, whereas the 
untethered hybrid toddler/booster restraint configuration resulted 
in unacceptable head and knee excursions, the untethered Roundabout 
configuration limited both head and knee excursion within acceptable 
limits (although only marginally

[[Page 36664]]

with respect to head excursion in the first test at 810.26 mm (31.90 
inches)). Additionally, while the untethered hybrid toddler/booster 
restraint tests resulted in reduced HIC and chest acceleration 
measurements, the untethered Roundabout tests resulted in reduced 
chest acceleration measurements but increased HIC values.
    The second convertible restraint, the Britax Elite, demonstrated 
similar results. In the tethered configuration, head excursion was 
limited to 640.08 and 580.39 mm (25.2 and 22.85 inches) in the two 
tests performed, again well below the 813 mm limit prescribed in the 
standard and also well below the results observed in the baseline 
test with the shield-type booster. Knee excursion measurements were 
also well below the established limit. However, each of the tests 
conducted in the untethered configuration resulted in head excursion 
measurements that marginally (820.02 and 821.69 mm) (32.29 and 32.35 
inches) exceed the 813 mm limit, while knee excursion measurements 
remained within acceptable limits.
    The two different E-Z On products, the Y-harness and the vest, 
are the only products currently marketed for children over 18 kg (40 
lb) that do not require the use of a shoulder harness to attach to 
the vehicle. Both of these systems require the use of a tether. Test 
results show that the Y-harness system dramatically limited head 
excursion to 495.3 and 473.71 mm (19.5 and 18.65 inches) on the two 
tests, or approximately 33 percent below the 813 mm limit prescribed 
in the standard, and significantly below the other tethered systems. 
Knee excursion was also limited to values well below established 
limits.
    E-Z On markets two different styles of the vest system. The 
first is an adjustable vest, which can be adjusted for fit as the 
child grows via three different zipper locations on the back of the 
vest. This was not used in this test program, as the vest, when 
configured in its smallest size, was still too large to properly fit 
the 6-year-old test dummy. E-Z On also manufactures sized vests, 
provided to the consumer based on anatomical measurements of the 
child as provided to E-Z On. NHTSA utilized a fitted vest in this 
testing program, although it should be noted that the vest provided 
by the manufacturer for this testing was very tight on the 6-year-
old dummy, and the next larger size would likely have provided a 
better fit. The E-Z On vest system was tested utilizing a top tether 
strap. The head and knee excursion values were both well below 
established limits. The chest acceleration was 59.3 g, marginally 
below the limit of 60 g. This high value for chest acceleration may 
be partially attributable to the very snug fit of the vest on the 
test dummy.
    Given the excessive head excursion measured in 17 of the 20 
tests performed in the Calspan and VRTC studies, combined with the 
assumption that child restraint manufacturers are not currently 
marketing shield-type booster seats for children over 18 kg due to 
an inability to meet the head excursion requirement when testing 
with the 6-year-old dummy, NHTSA chose to include only one 
representative shield-type booster seat (the Cosco Grand Explorer) 
to serve as a baseline test for the current test program. However, 
given the favorable results with respect to both head and knee 
excursion parameters seen with this seat as noted above, NHTSA 
conducted a second set of testing to evaluate three other currently 
available shield-type booster seats (the Gerry Double Guard, Evenflo 
Sidekick, and Fisher Price T-Shield). As before, each seat was 
tested twice, on separate test runs, to enhance the repeatability of 
the test results. In each instance, the measured head excursion 
significantly exceeded the 813 mm (32 inch) limit of Standard 213, 
ranging from 876.3 to 1016 mm (34.5 to 40.0 inches). Full test 
results are provided in Table 3. These results more closely parallel 
those recorded in the earlier tests conducted by Calspan and VRTC. 
Physical examination of each of the four shield-type booster seats 
tested in this test program revealed no obvious, discernable 
variations in construction, i.e., height of the shield, etc., that 
would explain the difference in performance of the Cosco Grand 
Explorer versus the others with respect to head excursion.

                                    Table 3.--Additional Shield Booster Tests
----------------------------------------------------------------------------------------------------------------
                                                                      Head          Knee
       Restraint configuration             HIC       3 ms chest     excursion     excursion        Test No.
                                                      clip (G)        (mm)          (mm)
----------------------------------------------------------------------------------------------------------------
FMVSS No. 213 limit..................         1000          60           813           914    ..................
Gerry Double Guard Lap Belt w/sm.              748          35.8         979.9         825.5  UMP21
 Shield.
Evenflo Sidekick Lap Belt w/sm.                721          37.8         873.8         762.0  UMP22
 Shield.
Fisher Price T-Shield Lap Belt w/sm.           349          26.1         927.1         767.1  UMP23
 Shield.
Evenflo Sidekick Lap Belt w/sm.                820          35.9         876.3         749.3  UMP24
 Shield.
Gerry Double Guard Lap Belt w/sm.              780          34.6        1016           838.2  UMP25
 Shield.
Fisher Price T-Shield Lap Belt w/sm.           525          31.5         955.0         784.9  UMP26
 Shield.
----------------------------------------------------------------------------------------------------------------

    Issued on June 29, 1999.
L. Robert Shelton,
Associate Administrator for Safety Performance Standards.
[FR Doc. 99-17235 Filed 7-6-99; 8:45 am]
BILLING CODE 4910-59-P