[Federal Register Volume 80, Number 194 (Wednesday, October 7, 2015)]
[Notices]
[Pages 60732-60735]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2015-25526]


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DEPARTMENT OF TRANSPORTATION

Federal Highway Administration

[FHWA Docket No. FHWA-2015-0020]


Revision of Thirteen Controlling Criteria for Design; Notice and 
Request for Comment

AGENCY: Federal Highway Administration (FHWA), DOT.

ACTION: Notice; request for comment.

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SUMMARY: The geometric design standards for projects on the National 
Highway System (NHS) are incorporated by reference in FHWA regulations. 
These design standards are comprehensive in nature, covering a 
multitude of design characteristics, while allowing flexibility in 
application. Exceptions may be approved on a project basis for designs 
that do not conform to the minimum or limiting criteria set forth in 
the standards, policies, and standard specifications.
    The FHWA is updating its policy regarding controlling criteria for 
design. The current policy identifies 13 controlling criteria for 
design and requires formal design exceptions when any of the 13 
controlling criteria are not met. The FHWA intends to further 
streamline the controlling criteria, and the application of these 
criteria, based on the results of recent research that evaluated the 
safety and operational effects of the 13 controlling criteria. The FHWA 
also intends to clarify when design exceptions are required and the 
documentation that is expected to support such requests. This notice 
solicits comments on the proposed revisions to the 13 controlling 
criteria for the design of projects on the NHS that require a design 
exception when adopted design criteria are not met, in accordance with 
FHWA regulations.

DATES: Comments must be received on or before December 7, 2015. Late 
comments will be considered to the extent practicable.

ADDRESSES: Mail or hand deliver comments to the U.S. Department of 
Transportation, Dockets Management Facility, Room W12-140, 1200 New 
Jersey Avenue SE., Washington, DC 20590, or fax comments to (202) 493-
2251. Alternatively, comments may be submitted to the Federal 
eRulemaking portal at http://www.regulations.gov. All comments must 
include the docket number that appears in the heading of this document. 
All comments received will be available for examination and copying at 
the above address from 9 a.m. to 5 p.m., e.t., Monday through Friday, 
except Federal holidays. Those desiring notification of receipt of 
comments must include a self-addressed, stamped postcard or you may 
print the acknowledgment page that appears after submitting comments 
electronically. Anyone is able to search the electronic form of all 
comments in any one of our dockets by the name of the individual 
submitting the comment (or signing the comment, if submitted on behalf 
of an association, business, or labor union). Anyone may review DOT's 
complete Privacy Act Statement in the Federal Register published on 
April 11, 2000 (Volume 65, Number 70, Pages 19477-78).

FOR FURTHER INFORMATION CONTACT: For questions about the program 
discussed herein, contact Elizabeth Hilton, Geometric Design Engineer, 
FHWA Office of Program Administration, (512) 536-5970 or via email at 
[email protected]. For legal questions, please contact Robert 
Black, Office of the Chief Counsel, (202) 366-1359, or via email at 
[email protected]. Office hours are from 8:00 a.m. to 4:30 p.m., 
e.t., Monday through Friday, except Federal holidays.

SUPPLEMENTARY INFORMATION: 

Electronic Access and Filing

    You may submit or retrieve comments online through the Federal 
eRulemaking portal at: http://www.regulations.gov. The Web site is 
available 24 hours each day, 365 days each year. Please follow the 
instructions. Electronic submission and retrieval help and guidelines 
are available under the help section of the Web site. An electronic 
copy of this document may also be downloaded from the Office of the 
Federal Register's home page at: http://www.archives.gov and the 
Government Printing Office's Web page at: http://www.access.gpo.gov/nara.

Purpose of This Notice

    The FHWA is requesting comment on proposed revisions to the 13 
controlling criteria for the design of projects on the NHS that require 
a design exception when not met, in accordance with 23 CFR 625.3(f). 
Design exceptions are an administrative tool used to document an 
engineer's evaluation of possible solutions to a specific design issue, 
including the operational and safety performance of each option, 
impacts to the human and natural environment, and other factors, and 
demonstrating the reasons a particular solution that does not meet 
applicable design standards was selected. Many States have their own 
process for reviewing design deviations when State or Federal design 
criteria are not met. When used in this Notice, the term `design 
exception' refers to documentation prepared for projects on the NHS 
when a controlling criterion is not met, and that must be approved by 
the FHWA or on behalf of FHWA if a State Transportation Agency (STA) 
has assumed this responsibility through a Stewardship and Oversight 
agreement. Stewardship and Oversight agreements set forth the agreement 
between FHWA and each STA on the roles and responsibilities of FHWA and 
the STA with respect to Title 23 project

[[Page 60733]]

approvals and related responsibilities and oversight activities. The 
FHWA also intends to clarify when design exceptions are required and 
the documentation that is expected to support such requests.
    Comments received through this Notice will be considered by FHWA 
when revising the controlling criteria for the design of projects on 
the NHS, as well as design exception documentation and application.

Background

    As codified in 23 CFR 625.3 and 625.4, the geometric design 
standards for projects on the NHS are A Policy on Geometric Design of 
Highways and Streets (2001) and A Policy on Design Standards Interstate 
System (2005), published by the American Association of State Highway 
and Transportation Officials (AASHTO). Rulemaking is underway to adopt 
the current (2011) edition of A Policy on Geometric Design of Highways 
and Streets. These design standards are comprehensive in nature, 
covering a multitude of design characteristics, while allowing 
flexibility in application. As codified in 23 CFR 625.3(f), and in 
accordance with the delegated authority provided by FHWA Order 
M1100.1A, exceptions may be approved on a project basis for designs 
that do not conform to the minimum or limiting criteria set forth in 
the standards, policies, and standard specifications adopted in 23 CFR 
part 625.
    The FHWA issued a policy memorandum on April 15, 1985, available on 
the docket for this notice, and on FHWA's Web site at http://www.fhwa.dot.gov/design/standards/850415.cfm, which identified 13 
criteria contained in A Policy on Geometric Design of Highways and 
Streets and designated them as controlling criteria. The policy 
required formal design exceptions when any of the 13 controlling 
criteria were not met.
    The FHWA proposes to streamline the 13 controlling criteria to 
refine the focus on criteria with the greatest impact on road safety 
and operation. This streamlined application of the controlling criteria 
is consistent with the industry's move toward a modified design 
approach, often referred to as performance based practical design 
(PBPD), and will reduce the instances when a design exception must be 
prepared when applicable design standards are not met for projects on 
the NHS. The controlling design criteria set forth in 1985 are: Design 
speed, lane width, shoulder width, bridge width, horizontal alignment, 
superelevation, vertical alignment, grade, stopping sight distance, 
cross slope, vertical clearance, horizontal clearance, and structural 
capacity. The term `horizontal clearance' was initially interpreted as 
the `clear zone' described in the AASHTO Roadside Design Guide (http://www.fhwa.dot.gov/design/standards/850415.cfm), but in the early 1990s 
was clarified to mean `lateral offset to obstruction' as described in 
the AASHTO geometric design policies (http://www.fhwa.dot.gov/design/standards/930525.cfm). Recent research, culminating in publications of 
the most recent Highway Capacity Manual (2010, Transportation Research 
Board) and the Highway Safety Manual (2010, AASHTO), developed much 
greater knowledge of the traffic operational and safety effects of the 
controlling criteria than was available when they were established. The 
NCHRP Report 783 ``Evaluation of the 13 Controlling Criteria for 
Geometric Design'' (2014) specifically examined the safety and 
operational effects of the existing controlling criteria.
    The PBPD is an approach to decisionmaking that encourages 
engineered solutions rather than relying on minimum, maximum, or 
limiting values found in design criteria. The PBPD is grounded in an 
analytic framework that enables transportation agencies to utilize 
existing design flexibility and analytical tools in a way that 
maximizes benefits while minimizing costs. The PBPD does not disregard 
engineering guidance or standards. Rather, flexibility in design 
typically requires more information and a higher level of analysis when 
defining and deciding on the most appropriate design value for a 
particular location. Consistent with FHWA's efforts regarding PBPD and 
to ensure that design exceptions are only required for criteria with 
significant safety or operational effects, FHWA intends to streamline 
the controlling criteria based on the findings of recent research. 
Since 1985, the controlling criteria have been applied to all projects, 
regardless of roadway type or context. The NCHRP Report 783 found that 
the 13 controlling criteria had minimal influence on the safety or 
operations on urban streets. On rural roadways, freeways, and high-
speed urban/suburban roadways, a stronger connection to safety and 
operations was found for some of the criteria than for others.

Proposed Revisions to Controlling Criteria

    Based on the findings of NCHRP Report 783 and FHWA's own assessment 
and experience, FHWA proposes to eliminate the following controlling 
criteria:
     Bridge Width.
     Vertical Alignment.
     Lateral Offset to Obstruction.
    To improve clarity, FHWA proposes to rename the following existing 
controlling criteria:
     Horizontal Alignment to be renamed Horizontal Curve 
Radius.
     Grade to be renamed Maximum Grade.
     Structural Capacity to be renamed Design Loading 
Structural Capacity.
    The resulting controlling criteria for design are proposed as 
follows:
     Design Speed.
     Lane Width.
     Shoulder Width.
     Horizontal Curve Radius.
     Superelevation.
     Stopping Sight Distance.
     Maximum Grade.
     Cross Slope.
     Vertical Clearance.
     Design Loading Structural Capacity.
    The FHWA also proposes a revision to the application of the 
controlling criteria. Most controlling criteria would apply only to 
high-speed [design speed >=50 mph (80 km/h)] roadways. Only design 
loading structural capacity and design speed would continue to be 
applied to all NHS facility types. Research indicates that the current 
controlling criteria are less influential on the traffic operational 
and safety performance of low-speed urban and suburban arterials than 
other features such as intersection design and access management 
strategies. Therefore, consistent with FHWA's risk-based approach to 
stewardship and oversight, FHWA intends to focus application of the 
controlling criteria on high-speed NHS roadways [design speed >= 50 mph 
(80 km/h)]. On low-speed NHS roadways [design speed <50 mph (80 km/h)], 
design exceptions are proposed to only be required by FHWA for 
deviations from the design speed or design loading structural capacity 
criteria. Exceptions to the controlling criteria must be carefully 
evaluated and approved by FHWA or on behalf of FHWA if an STA has 
assumed the responsibility through a Stewardship and Oversight 
agreement.
    While all of the criteria contained in the adopted standards are 
important design considerations, they do not all affect the safety and 
operations of a roadway to the same degree, and therefore should not 
require the same level of administrative control. Based on the findings 
of recent research and FHWA's assessment and experience, a brief 
discussion on each of the proposed changes to the controlling criteria 
is provided below.

[[Page 60734]]

Controlling Criteria FHWA Proposes To Eliminate
    1. Bridge width is proposed to be removed from the list of 
controlling criteria because research found little relationship between 
bridge width and crash frequency on rural, two-lane highways and 
surmised the same would be true for other roadway types. Lane and 
shoulder width criteria apply to roadways and bridges, so any 
deficiency in bridge width will require design exception documentation 
if the lane or shoulder width criteria is not met under this proposal. 
Design criteria allow lesser shoulder width, and therefore lesser 
bridge widths, on long bridges [overall length over 200 feet (60 m)]. 
If the minimum lane or shoulder widths are not provided on a long 
bridge, the deviation would be documented as a lane or shoulder width 
design exception under the proposed revisions to controlling criteria.
    2. Vertical alignment is proposed to be removed from the list of 
controlling criteria. Three of the existing criteria relate to vertical 
alignment. Crest vertical curve design is covered under the stopping 
sight distance criterion. Grade is explicitly covered as a separate 
criterion, leaving only sag vertical curve length to be covered under 
the vertical alignment criterion. While research has confirmed the 
interrelationship between vehicle headlight illuminations, sag vertical 
curves, and sight distance to features in the roadway, no relationship 
has extended to the effect of these combined elements on crashes. 
Furthermore, except when a horizontal curve or overhead structure is 
also present, sag vertical curve length is not critical under daytime 
conditions when the driver can see beyond the sag vertical curve, or at 
night, when vehicle taillights and headlights make another vehicle on 
the road ahead visible in or beyond a sag vertical curve.
    3. Lateral offset to obstruction is proposed to be removed from the 
list of controlling criteria because on rural roadways, the controlling 
criterion for shoulder width ensures that there will be at least 18 
inches of lateral offset to roadside objects. Lateral offset is most 
relevant to urban and suburban roadways to ensure that mirrors or other 
appurtenances of heavy vehicles do not strike roadway objects and so 
that passengers in parked cars are able to open their doors. While 
these are important considerations, they do not rise to the same level 
of effect as other controlling criteria proposed to be retained.
Controlling Criteria FHWA Proposes To Retain for Roadways on the NHS 
With a Design Speed Equal to or Greater Than 50 mph (80 km/h), Unless 
Otherwise Noted
    1. Design speed is proposed to be retained as a controlling 
criterion for all facilities on the NHS. Design speed is different from 
the other controlling criteria in that it establishes the range of 
design values for many of the other geometric elements of the highway. 
Because of its effect on a highway's design, the design speed is a 
fundamental and very important choice that a designer makes. In 
recognition of the wide range of site-specific conditions, constraints, 
and contexts that designers face, the design standards allow a great 
deal of design flexibility by providing ranges of values for design 
speed. For most cases, the ranges provide adequate flexibility for 
designers to choose an appropriate design speed without the need for a 
design exception. If a limited portion of an alignment must be designed 
to a lower speed, it is generally more appropriate to evaluate specific 
geometric element(s) and treat those as design exceptions, instead of 
evaluating an exception for the design speed of the roadway.
    2. Lane width is an important design criterion with respect to 
crash frequency and traffic operations on high-speed and rural 
highways. The design standards provide the flexibility to choose lane 
widths as narrow as 10 feet on some facilities.
    3. Shoulder width has substantial effect on crash frequency and on 
traffic speeds on rural highways.
    4. Horizontal curve radius, previously called horizontal alignment, 
has a documented relationship to crash frequency on rural highways of 
all types. Curve radius also influences traffic operations on urban/
suburban arterials. Superelevation is the other main aspect of 
horizontal alignment and is being retained as independent controlling 
criterion.
    5. Superelevation has a documented relationship to crash frequency 
on rural, two-lane highways and research suggests this would also be 
true on rural multilane highways and freeways. Superelevation is 
generally not provided on low-speed urban/suburban streets.
    6. Stopping Sight Distance (SSD) is proposed to be retained as a 
controlling criterion because sufficiently long SSD is needed to enable 
a vehicle traveling at or near the design speed to stop before reaching 
a stationary object in its path. Research found that SSD less than 
specified by the design standards for crest vertical curve design, 
combined with a hidden feature such as a curve, intersection, or 
driveway, resulted in increased crashes on high speed roadways. 
Retention of SSD as a controlling criterion will ensure that deviations 
from this criterion are examined on a case-by-case basis, to determine 
whether site characteristics and crash history are indicative of 
potential areas needing attention. From an operational perspective, SSD 
generally does not affect operations on freeways under free-flow 
conditions. However, when freeways operate at near-capacity, limited 
SSD may further reduce capacity below the levels expected based on 
current predictive models. These impacts are typically examined during 
project development.
    7. Maximum grade is proposed as a controlling criterion but minimum 
grade is not. The existing controlling criteria of `grade' includes 
both maximum and minimum grade. Maximum grade is proposed to be 
retained due to its relationship to crash frequency on rural, two-lane 
highways and the effect of steep grades on traffic operations on high-
speed roadways. Minimum grade is proposed to be excluded because while 
it does influence roadway drainage, minimum grade alone does not ensure 
sufficient drainage and does not rise to the level of the controlling 
criteria.
    8. Cross slope is proposed to be retained as a controlling 
criterion to address drainage issues. While research has not been 
conducted to determine whether there is a relationship between the 
normal cross slope of roadway pavements and crash frequency, our 
experience is that inadequate drainage could contribute to vehicle loss 
of control under some circumstances. Due to the relationship between 
cross slope and drainage, especially when combined with minimum grades, 
cross slope is proposed to be retained as a controlling criterion.
    9. Vertical clearance is proposed to be retained as a controlling 
criterion. While vertical clearance does not affect operations on the 
roadway other than for those vehicles that are taller than the 
available vertical clearance allows, vertical clearance crashes can 
have severe impacts on operations by damaging overpasses and other 
structures, resulting in extended road closures. In addition, 
inadequate vertical clearance on Interstate freeways impacts military 
defense routes and requires additional coordination with the Surface 
Deployment and Distribution Command Transportation Engineering Agency.

[[Page 60735]]

    10. Design Loading Structural Capacity is related to the strength 
and service limit state designs, not to traffic operations or the 
likelihood of traffic crashes. Previously called `structural capacity,' 
FHWA proposes to clarify that the applicable criterion covered herein 
relates to the design of the structure, not the load rating. Design 
loading structural capacity is important in maintaining a consistent 
minimum standard for safe load-carrying capacity and deviations from 
this criterion should be extremely rare. Design loading structural 
capacity is proposed to be retained as a controlling criterion 
regardless of the design speed for the project. Exceptions to design 
loading structural capacity on the NHS could impact the mobility of 
freight, emergency and military vehicles, and the traveling public and 
requires additional coordination with the FHWA Office of 
Infrastructure.

Design Documentation

    As codified in 23 CFR 625.3(f), and in accordance with the 
delegated authority provided by FHWA Order M1100.1A, exceptions may be 
approved on a project basis for designs that do not conform to the 
minimum or limiting criteria set forth in the standards, policies, and 
standard specifications adopted in 23 CFR part 625. Under this 
proposal, formal design exceptions, subject to approval by FHWA, or on 
behalf of FHWA if an STA has assumed the responsibility through a 
Stewardship and Oversight agreement, would be required for projects on 
the NHS only when the controlling criteria are not met. The FHWA 
expects documentation of design exceptions to include all of the 
following:
     Specific design criteria that will not be met.
     Existing roadway characteristics.
     Alternatives considered.
     Analysis of standard criteria versus proposed design 
criteria.
    [cir] Supporting quantitative analysis of expected operational and 
safety performance.
    [cir] Right-of-way impacts.
    [cir] Impacts to human and natural environment.
    [cir] Impacts to the community.
    [cir] Impacts on the needs of all users of the facility.
    [cir] Project cost.
     Proposed mitigation measures.
     Compatibility with adjacent sections of roadway.
     Possibility of a future project bringing this section into 
compliance with applicable standards.
    Design Speed and Design Loading Structural Capacity are fundamental 
criteria in the design of a project. Exceptions to these criteria 
should be extremely rare and FHWA expects the documentation to provide 
the following additional information.
     Design Speed exceptions must address:
    [cir] Length of section with reduced design speed compared to 
overall length of project.
    [cir] Measures used in transitions to adjacent sections with higher 
or lower design or operating speeds.
     Design Loading Structural Capacity exceptions must 
address:
    [cir] Verification of safe load-carrying capacity (load rating) for 
all State unrestricted legal loads or routine permit loads, and in the 
case of bridges on the Interstate, all Federal legal loads.
    The FHWA encourages agencies to document all design decisions to 
demonstrate compliance with accepted engineering principles and the 
reasons for the decision. Deviations from criteria contained in the 
standards for projects on the NHS, but which are not considered to be 
controlling criteria, should be documented by the STA in accordance 
with State laws, regulations, directives, and safety standards. 
Deviations from criteria contained in standards adopted by a State for 
projects not on the NHS should be documented in accordance with State 
laws, regulations, directives, and safety standards. States can 
determine their own level of documentation depending on their State 
laws and risk management practices.
    The proposed revisions to the controlling criteria and design 
documentation requirements will be published in final form after 
considering comments received regarding the proposed changes.
    The FHWA requests comments on the revised guidance memorandum, 
which is available in the docket (FHWA-2015-0020). The FHWA will 
respond to comments received on the guidance in a second Federal 
Register notice, to be published after the close of the comment period. 
That second notice will include the final guidance memorandum that 
reflects any changes implemented as a result of comments received.

    Authority:  23 U.S.C. 109 and 315; 23 CFR 1.32 and 625; 49 CFR 
1.85.

    Issued on: September 30, 2015.
Gregory G. Nadeau,
Administrator, Federal Highway Administration.
[FR Doc. 2015-25526 Filed 10-6-15; 8:45 am]
 BILLING CODE 4910-22-P