Revision of Thirteen Controlling Criteria for Design and Documentation of Design Exceptions |
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Gregory G. Nadeau
Federal Highway Administration
5 May 2016
[Federal Register Volume 81, Number 87 (Thursday, May 5, 2016)]
[Notices]
[Pages 27187-27191]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2016-10299]
[[Page 27187]]
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DEPARTMENT OF TRANSPORTATION
Federal Highway Administration
[FHWA Docket No. FHWA-2015-0020]
Revision of Thirteen Controlling Criteria for Design and
Documentation of Design Exceptions
AGENCY: Federal Highway Administration (FHWA), Department of
Transportation (DOT).
ACTION: Notice.
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SUMMARY: The geometric design standards for projects on the National
Highway System (NHS) are incorporated by reference in FHWA regulations
in 23 CFR 625 and apply regardless of funding source. 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 1985 policy regarding controlling criteria
for design, applicable to projects on the NHS, to reduce the number of
controlling criteria from 13 to 10, and to apply only 2 of those
criteria to low speed roadways. The FHWA is also issuing guidance to
clarify when design exceptions are needed and the documentation that is
expected to support such requests. The FHWA's guidance memorandum,
which is available in the docket (FHWA-2015-0020), transmits this
policy to FHWA field offices.
FOR FURTHER INFORMATION CONTACT: For questions, contact Elizabeth
Hilton, Geometric Design Engineer, FHWA Office of Program
Administration, telephone 512-536-5970, or via email at
Elizabeth.Hilton@dot.gov. For legal questions, please contact Robert
Black, Office of the Chief Counsel, telephone 202-366-1359, or via
email at Robert.Black@dot.gov, Federal Highway Administration, 1200 New
Jersey Avenue SE., Washington, DC 20590. Business hours for the FHWA
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
This document, the request for comments notice, and all comments
received may be viewed online through the Federal eRulemaking portal
at: http://www.regulations.gov. The docket identification number is
FHWA-2015-0020. The Web site is available 24 hours each day, 365 days
each year. Anyone can search the electronic form of all comments in any
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). You may review DOT's complete Privacy Act
Statement in the Federal Register published on April 11, 2000 (65 FR
19477), or you may visit http://DocketsInfo.dot.gov.
Request for Comments
On October 7, 2015, FHWA published a Notice with Request for
Comments (80 FR 60732) soliciting public comments on proposed revisions
to the 13 controlling criteria for the design and the documentation
that is expected to support requests for design exceptions. 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 in accordance with 23 CFR 625.3(f), by
FHWA or on behalf of FHWA if a State Transportation Agency (STA) has
assumed this responsibility through a Stewardship and Oversight
agreement.
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 (2011) and A Policy on Design Standards Interstate
System (2005), published by the American Association of State Highway
and Transportation Officials (AASHTO). As codified in 23 CFR 625.3(f),
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 625. In 1985,
FHWA designated 13 criteria as controlling criteria, requiring design
exceptions when any of these 13 criteria were not met.
The FHWA proposed to eliminate 3 criteria, rename others, and focus
the application of most criteria on high-speed roadways (i.e., design
speed >=50 mph). The 10 controlling criteria proposed for design of
projects on the NHS were: Design Speed, Lane Width, Shoulder Width,
Horizontal Curve Radius, Superelevation, Stopping Sight Distance,
Maximum Grade, Cross Slope, Vertical Clearance, and Design Loading
Structural Capacity. The FHWA proposed that all 10 controlling criteria
would apply to high-speed roadways on the NHS, and that only two,
Design Speed and Design Loading Structural Capacity, would apply on
low-speed roadways (i.e., design speed <50 mph) on the NHS.
Purpose of the Notice
The purpose of this notice is to publish final designation of the
controlling criteria for design of projects on the NHS and how they
will be applied in various contexts, and describe the design
documentation needed to support requests for design exceptions. 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 do not require the same
level of administrative control. The FHWA encourages agencies to
document 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 which
are not considered to be controlling criteria should be documented by
the STA in accordance with State laws, regulations, directives, and
safety standards. States can determine their own level of documentation
depending on State laws and risk management practices.
Designation of Controlling Criteria
Based on the comments received in response to FHWA's proposal,
combined with FHWA's own experience and the findings of National
Cooperative Highway Research Program (NCHRP) Report 783 ``Evaluation of
the 13 Controlling Criteria for Geometric Design'' (2014), the 10
controlling criteria for design are:
Design Speed;
Lane Width;
Shoulder Width;
Horizontal Curve Radius;
Superelevation Rate;
Stopping Sight Distance (SSD);
Maximum Grade;
Cross Slope;
Vertical Clearance; and
Design Loading Structural Capacity.
All 10 controlling criteria apply to high-speed (i.e., Interstate
highways, other freeways, and roadways with design speed >=50 mph)
roadways on the NHS. The SSD applies to horizontal alignments and
vertical alignments except for sag vertical curves. On low-speed
roadways (i.e., non-freeways with design speed <50 mph) on the NHS,
only the following two controlling criteria apply:
Design Loading Structural Capacity; and
Design Speed.
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Design Documentation
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, are required for projects on the NHS only when the
controlling criteria are not met. The FHWA expects documentation of
design exceptions to describe all of the following:
Specific design criteria that will not be met.
Existing roadway characteristics.
Alternatives considered.
Comparison of the safety and operational performance of
the roadway and other impacts such as right-of-way, community,
environmental, cost, and usability by all modes of transportation.
Proposed mitigation measures.
Compatibility with adjacent sections of roadway.
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:
[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:
[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 and tunnels 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. The approval of deviations from applicable
design criteria are to be handled as follows:
1. The project is located on a NHS roadway and controlling criteria
are not met: In accordance with 23 CFR 625.3(f), design exceptions are
required and FHWA is the approving authority, or exceptions may be
approved on behalf of FHWA if an STA has assumed the responsibility
through a Stewardship and Oversight agreement, with documentation as
stated above.
2. The project is located on a NHS roadway and non-controlling
criteria are not met: STA is the approving authority for design
deviations,\1\ in accordance with State laws, regulations, directives,
and safety standards. States can determine their own level of
documentation depending on State laws and risk management practices.
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\1\ The term ``deviation,'' when used in this document, refers
to any departure from design criteria that does not require FHWA
approval because either the criteria is non-controlling or the
facility is not on the NHS. States often refer to these instances as
design deviations or variances.
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3. The project is located on a non-NHS roadway and the State design
criteria are not met on a Federal-aid project: STA is the approving
authority for design deviations, 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.
Analysis of Comments
The FHWA received comments from 2,327 individuals and organizations
on the proposed changes to the controlling criteria. Of these, 2,167
were individual form-letter comments delivered to the docket by
Transportation for America. Of the remaining, 87 were from individuals,
23 from STAs, 22 from other public entities, 18 from private
organizations, 5 from industry associations, 4 from private firms, and
1 from an elected official. The comments are summarized below.
General Comments
Many commenters referred to the proposed changes as a rulemaking.
The controlling criteria are not established by Federal regulation,
instead they are a matter of policy. The proposed changes are not a
rulemaking as they will not modify the CFR and will not impose binding
requirements that have the force and effect of law. The proposal was
published as a notice in the Federal Register as a way to invite public
comment on the proposed policy changes.
Controlling Criteria
All but 7 of the 2,327 commenters support revisions to the
controlling criteria. Some supporters suggested changes which were
considered by FHWA, as shown below.
1. Over 2,100 commenters asked FHWA to replace the term ``design
speed'' with ``target speed'' for low-speed NHS roadways so that
roadway design elements could be selected to meet community needs and
provide safety for all modes of transportation.
Response: No changes were made. The proposed changes, combined with
recent clarification by FHWA about design speeds and posted speeds
(available at http://www.fhwa.dot.gov/design/standards/151007.cfm),
allow agencies the flexibility to design based on target speed while
remaining consistent with the terminology used in the adopted AASHTO
standards. The FHWA forwarded this comment to the AASHTO Technical
Committee on Geometric Design for its consideration.
2. The National Association of City Transportation Officials asked
FHWA to clarify that there is no minimum design speed.
Response: No changes were made. Minimum design speeds are included
in the adopted standards for the NHS and design exceptions are required
if a lower design speed is selected. The FHWA forwarded this comment to
the AASHTO Technical Committee on Geometric Design for its
consideration.
3. Three STAs recommended retaining vertical clearance as a
controlling criterion on low-speed roadways to ensure that insufficient
vertical clearance on a minor roadway would not result in damage to an
overpassing high-speed roadway, such as an Interstate highway or other
freeway.
Response: No changes were made. The FHWA agrees that vertical
clearance is an important criterion and that insufficient clearance on
one roadway may negatively impact the overpassing roadway. However,
States are already managing the scenario described if the low-speed
roadway is not on the NHS. Under this revised policy, States would
continue to manage the risks associated with insufficient vertical
clearance for all low-speed roadways (non-freeway), including those on
the NHS.
4. The Oregon DOT and a few individuals thought that 50 mph was too
high for the threshold between high- and low-speed roadways, citing
concerns about urban expressways and that freight vehicles need wider
lanes.
Response: The speed threshold remains unchanged. The intent was to
capture all freeways in the high-speed category. For clarification,
FHWA revised the definition of high-speed roadway for the purposes of
this policy to include all Interstate highways, other freeways, and
roadways with design speed greater than or equal to 50 mph.
5. The Wisconsin DOT recommended using a posted speed of 40 mph to
define the threshold, stating that a design speed of 50 mph is too high
given the likelihood of pedestrian fatalities at that speed.
Response: No changes were made. The proposed threshold was chosen
for consistency with AASHTO policy documents adopted through regulation
at 23 CFR 625.4. The policy allows maximum design flexibility for roads
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with a design speed less than 50 mph which can be applied in ways that
improve pedestrian safety.
6. The Indiana DOT asked FHWA to clarify that the superelevation
criterion is for rate only, and that transition length and distribution
are not subject to a design exception.
Response: The FHWA concurs and clarified the term in the
controlling criteria list.
7. The Indiana DOT asked FHWA to clarify the application of SSD to
vertical and horizontal curves.
Response: Clarification was added. The SSD applies to a variety of
situations and is well described in A Policy on Geometric Design of
Highways and Streets (2011). As noted in NCHRP Report 783, SSD has
little impact on the safety and operations at sag vertical curves 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.
Therefore, the application of SSD at sag vertical curves is excluded
from the controlling criterion.
8. The Minnesota DOT suggested eliminating design speed as a
controlling criterion on low-speed roadways.
Response: No changes were made. Design speed must be retained
because it is a fundamental criterion in the design of the project and
because it sets the threshold for application of the controlling
criteria. If, for example, design speed was not a controlling criterion
for low-speed roadways, practitioners could simply select a lower
design speed to avoid the controlling criteria requirements for high-
speed roadways.
9. The Georgia DOT and two others commented that lateral offset to
obstruction should be retained as a controlling criterion.
Response: No changes were made. 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
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 and do not
require the same level of administrative control.
10. The Wisconsin DOT recommended retaining lane width,
superelevation, stopping sight distance, and cross slope as controlling
criteria for low-speed roadways, and adding a new controlling criterion
for critical length of grade.
Response: No changes were made. The FHWA finds that removing these
controlling criteria from application in low-speed environments is
supported by research and provides additional flexibility to better
accommodate all modes of transportation. No new controlling criteria
are proposed at this time.
11. The Wisconsin DOT commented that bridge width is not redundant
if lane and shoulder widths are dropped from the controlling criteria
list in the low-speed environment, which may result in choke points
that are expensive to correct. They also commented that vertical and
horizontal clearances can influence structural ratings; that stopping
sight distances at intersections can be critical; and that the
combination of flat grades and cross slopes is problematic.
Response: No changes were made. While these criteria are important,
the risk of deviations can be handled by STAs in accordance with their
risk management practices.
12. The Wisconsin DOT asked why clear zone was not included in the
updated controlling criteria.
Response: No changes were made. The Roadside Design Guide was not
adopted as a standard under 23 CFR 625. Instead it serves as guidance
with regard to roadside safety. Therefore, adoption of values in the
Roadside Design Guide as controlling criteria would not be appropriate.
13. A few commenters asked FHWA to adopt additional controlling
criteria to require the provision of bicycle and/or pedestrian
facilities on roadways.
Response: No changes were made. Such a policy would require a
regulatory change which is beyond the scope of this controlling
criteria policy.
Several commenters supporting changes to the 1985 policy requested
clarifying guidance in the final notice, as follows:
1. Clarify requirements for non-NHS Federal-aid projects.
Response: This policy change does not modify existing regulations.
Per 23 CFR 625.3(a)(2), ``Federal-aid projects not on the NHS are to be
designed, constructed, operated, and maintained in accordance with
State laws, regulations, directives, safety standards, design
standards, and construction standards.'' The FHWA reiterated in this
notice that the controlling criteria apply only to the NHS.
2. Limit application on the NHS to new construction and
reconstruction projects, and/or clarify that the proposed modifications
will not reduce current State flexibility regarding projects that are
not new construction or reconstruction.
Response: This policy change does not modify existing regulations.
It is not limited to new construction and reconstruction projects on
the NHS. Title 23 CFR 625.4(a)(3) states that ``resurfacing,
restoration, and rehabilitation (RRR) projects on NHS highways other
than freeways'' may utilize the design criteria established by the
State and approved by FHWA. The regulations do not allow the adoption
of RRR criteria for NHS freeways. The FHWA Division Administrator is
allowed to determine the applicability of the roadway geometric design
standards to traffic engineering, safety, and preventive maintenance
projects which include very minor or no roadway work under 23 CFR
625.3(e).
3. One commenter asked FHWA to clarify that States can be more
restrictive than Federal guidance proposed here, while other commenters
asked FHWA to encourage State DOTs to apply the same logic to non-NHS
facilities.
Response: States may adopt policies that are more restrictive than
the revised FHWA policy published here. The FHWA encourages agencies to
work together with stakeholders to develop context sensitive solutions
that enhance communities and provide multiple transportation options to
connect people to work, school, and other critical destinations. The
FHWA notes that the Fixing America's Surface Transportation (FAST) Act
of 2015 includes new provisions encouraging design flexibility. The
FHWA also issued a memorandum in 2013 expressing support for taking a
flexible approach to bicycle and pedestrian facility design. The
memorandum is available at http://www.fhwa.dot.gov/environment/bicycle_pedestrian/guidance/design_flexibility.cfm.
4. A few commenters expressed concern that FHWA is abandoning
safety on low speed roadways, or that some designers will view non-
controlling criteria as less important.
Response: The FHWA developed this proposal, based on the findings
in NCHRP Report 783 and FHWA's experience, to give agencies the
flexibility to balance the safety and operations of all modes of
transportation, while reducing administrative requirements where they
do not clearly result in improved safety and operations. The FHWA
encourages agencies to document all design decisions to demonstrate
compliance with accepted engineering principles and the reasons for the
decision.
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Deviations from criteria contained in the standards for projects on the
NHS which are not considered to be controlling criteria should be
documented by the STA in accordance with State laws, regulations,
directives, and safety standards. States can determine their own level
of documentation depending on State laws and risk management practices.
Agencies are responsible for the training and development of their
employees.
5. Clarify that design exceptions are not required for non-
controlling criteria.
Response: Clarifying language was added to the Design Documentation
section that stated design exceptions are not required for non-
controlling criteria.
6. For low-speed roadways, clarify that elements dependent on
design speed that are substandard do not require a design exception.
For example, design speed is 40 mph (and does not require a design
exception), but the minimum curve radius provided meets 35 mph (no
design exception is required).
Response: For non-freeways, the controlling criteria categories are
based on design speed, which puts the project in one of two groups:
High-speed or low-speed. Within each category, design exceptions are
only required when the controlling criteria are not met. In the example
provided, a non-freeway with a 40 mph design speed in accordance with
the AASHTO criteria would be classified as low-speed. Design exceptions
would only be required if the design speed or design loading structural
capacity criteria were not met. No changes were made to the text of the
policy.
7. The Wisconsin DOT asked what will be allowed for the National
Network (Federally designated long truck routes per 23 CFR 658) if lane
and shoulder widths are not important for safety and operations.
Response: 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. Changes to the
controlling criteria policy do not modify the regulations contained in
23 CFR 658.
8. The Wisconsin DOT asked what consideration was given to oversize
and overweight vehicles.
Response: As noted in Chapter 2 of the A Policy on Geometric Design
of Highways and Streets, the designer should consider the largest
design vehicle that is likely to use that facility with considerable
frequency or a design vehicle with special characteristics appropriate
to a particular location in determining the design of such critical
features as radii at intersections and radii of turning roadways.
Designers are responsible for proper consideration of oversize and
overweight vehicles and all other aspects of the project context.
9. The Southern Environmental Law Center asked FHWA to clarify
whether rural roads with a design speed of less than 50 mph remain
subject to the 10 remaining design criteria.
Response: No changes were made. The application of the controlling
criteria is the same regardless of urban or rural designation.
Seven private citizens oppose changes to the controlling criteria
policy. Five of the seven who oppose the changes believe the proposed
flexibility will divert scarce Federal gasoline and road taxes to non-
highway purposes.
No changes were made as a result of these comments. The design
standards for the NHS and design exception process apply regardless of
project funding. Revising the controlling criteria gives communities
the ability to develop a transportation system that best serves their
needs, but does not change existing laws or regulations pertaining to
project expenses eligible for Federal reimbursement.
Several comments were received that do not pertain directly to the
controlling criteria policy. The Southern Environmental Law Center
recommends changes to the design speeds shown in the AASHTO Green Book
to reflect a range instead of a single minimum number, as currently
shown for three of the categories (rural freeway, urban freeway, and
urban collector). The criterion for urban collectors should vary
according to the different types of terrain. Likewise, the low end of
the design speed range for urban collectors in mountainous terrain
should be the same 20 mph minimum used for collectors in rural
mountainous terrain. Finally, the definition of the term ``urban''
should be revised to include areas of low density sprawl that now
surround most cities.
This comment is outside the scope of this notice. The FHWA
forwarded this comment to the AASHTO Technical Committee on Geometric
Design for its consideration.
Comments pertaining to the need for bicycle and pedestrian
accommodation on bridges; appraisal ratings contained in the National
Bridge Inspection Standards; the definition of pavement reconstruction;
design loading for military vehicles; and the methods for determining
posted speeds were also received.
These comments are outside the scope of this notice but were
forwarded to the appropriate program office within FHWA for
consideration.
Design Exception Documentation
Sixteen commenters provided comments on the proposed documentation
expected in support of requests for design exceptions. Fourteen STAs,
AASHTO, and the Chicago DOT all commented that the level of
documentation proposed for design exceptions would be burdensome and
would result in less flexibility than currently exists for roadways
with a design speed greater than 50 mph. They also believe that such a
requirement is at odds with FHWA's current emphasis on Performance
Based Practical Design (PBPD). Instead of providing an inclusive list
of items to be addressed in design documentation, they recommend that
any list be more suggestive in nature. Agencies asked FHWA to remove
the requirement for quantitative operational and safety analysis, and
expressed concern that references to the environment and community
would add too much specificity.
The PBPD is a design-up approach to address the purpose and need of
a project and emphasizes the need to document design decisions made
under this approach. Therefore, FHWA sees no inconsistency between the
design documentation proposed here and the PBPD approach. In response
to the concerns expressed, FHWA modified the language regarding the
safety and operational analysis such that it does not require a
quantitative analysis in all cases. The level of analysis should be
commensurate with the complexity of the project. The FHWA notes
however, that the FAST Act adds the Highway Safety Manual (HSM) to the
list of publications FHWA shall consider when developing design
criteria for the NHS. The FHWA strongly encourages agencies to utilize
the HSM procedures to the maximum extent applicable. The FHWA retained
references to the environment and community because design exceptions
to address these concerns are not uncommon, and therefore need to be a
part of any documentation.
Conclusion
The overwhelming support for changes to the controlling criteria
indicate that the changes will support agency and community efforts to
develop transportation projects that support community goals and are
appropriate to the project context. The provisions included here for
design documentation will result in more
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consistent evaluation of exceptions to the adopted design standards
when controlling criteria are not met on NHS highways.
Authority: 23 U.S.C. 109 and 315; 23 CFR 1.32 and 625; 49 CFR
1.85.
Issued on: April 22, 2016.
Gregory G. Nadeau,
Administrator, Federal Highway Administration.
[FR Doc. 2016-10299 Filed 5-4-16; 8:45 am]
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