American
Association of State Highway and Transportation Officials
Special Committee on
Research and Innovation
FY2023 NCHRP PROBLEM
STATEMENT
Problem Number: 2023-B-03
A common approach used in transportation engineering and
design is to set minimum accommodations or guidelines, such as a minimum width
for a sidewalk or bike lane or a minimum number of bike parking spaces. Such
guidelines provide for a basic level of infrastructure quality in cases where
they are applied. The concept is also used at the planning level, for example,
some Complete Streets policies specify minimum accommodations for pedestrians
and bicycles. However, the minimum accommodations are frequently used as the
default or preferred width, despite the fact that these widths are unlikely to
provide a level and quality that will increase the use of walking, bicycling,
and rolling significantly, particularly among all types of users and in areas
where greater walking, bicycling, and rolling activity is possible. Research is
needed on the design flexibility and the different levels of accommodation recommended
for different context and roadway types.
There is very limited research on the effects of minimum
accommodations and standards on the provision of active transportation
infrastructure. Schultheiss, Sanders, and Toole (2018) documented that there
was a limited evidence base available to inform changes in standards in the
AASHTO Bike Guide.
Lessons from experience in using Performance-based Practical
Design (PBPD) may also be useful. PBPD
uses a "design up" approach that relies more on engineering judgment
to identify improvements to meet project and system objectives.
Decisions are based on performance analysis (FHWA, 2017; Mooney, 2015).
Existing research on different decision-making methods may inform this research.
For example, multicriteria decision-making techniques consider multiple
criteria using both quantitative and qualitative data. A recent research review
found applications across the transportation sector, though it was used
primarily for project selection, rather than project design (Yannis et al.,
2020).
A current project, NCHRP 15-78 Guidebook for Urban and
Suburban Roadway Cross-Sectional Reallocation, may provide some research
related to this topic, including alternative approaches. The project’s
objective “is to develop a guidebook and decision-making framework
for roadway designers, planners, and others for identifying, comparing,
evaluating, and justifying context-based cross-sectional reallocations of
existing urban and suburban roadway space for multimodal safety, access,
and mobility.” The project began in June 2020.
This research will address design flexibility and the different levels of
accommodation recommended for different context and roadway types. The
objective of this research is to understand (1) how the use of minimum
accommodations may limit active transportation, and (2) what alternative
approaches and design flexibilities would result in recommendations for different levels of
accommodation for different context and roadway types to
better serve all road users. The research aims to understand this in different
contexts, with a focus on the design and engineering of roadways and
intersections.
Possible components of alternative approaches include:
·
Basing
decisions on desired performance. In such an approach, an agency would set an
objective for what they want to achieve with respect to active travel (e.g.,
specific pedestrian and bicycle mode shares) and use guidance and research to
design a solution to accommodate that performance goal. That objective could
also be based on certain “design users” or, for example, on having most people
of younger and older ages feel comfortable using the facility (e.g., “all ages
all abilities” or “eight to eighty”).
·
Analyses
that clearly indicates who would be accommodated with the minimum guidelines
(e.g., what percentage of the population would feel comfortable using the
facility walking, bicycling, or rolling) and how that would change with
different designs.
·
A
safe-systems approach that includes expectations for safety outcomes. This
would explicitly acknowledge that some users are at higher risk.
·
Changing
the language and framing. Under this approach, agencies would set preferred
levels of accommodation and lower values that would only be used in constrained
conditions.
Research tasks would include the following:
1.
A
review of existing research on minimum accommodations, design guidelines, and
alternative decision-making techniques.
2.
Empirical
research to assess how the use of such minimum accommodations has affected the
provision of infrastructure for active transportation in the U.S. and to what
extent agencies do or do not exceed minimums. This research would involve case
studies, surveys of practitioners, and other data collection approaches. The
research would also identify the reasons for not exceeding minimums.
3.
Identification
and evaluation of alternative approaches, design flexibilities, and/or ways of
presenting guidelines, to better serve all active transportation users in the
design of roadways and intersections by recommending different levels of
accommodation for different context and roadway types. The approaches should be
context-specific and include consideration of factors such as stormwater and
green infrastructure design. The research should draw on examples in the U.S.
as well as other countries.
4.
Produce
a report with the findings of the empirical research, including options for
addressing the reasons agencies may not often exceed minimum accommodations.
These may include, but are not limited to, technology transfer efforts to
expand the use of existing research and guidance, developing new research to
address gaps, changing agency culture, increased funding, and policy change.
5.
Develop
a guidebook that explains the advantages and disadvantages of minimum
accommodations and provides step-by-step guidance on alternative approaches and
design flexibilities that better serve all active transportation users by
recommending different levels of accommodation for different context and
roadway types. This would include case studies.
The final report and guidebook would be key tools for
implementation. In addition, the results of the project could be a good
candidate for the NCHRP Implementation Support Program (Project 20-44) to
develop training or pilot projects to implement alternative approaches.
The results of the research would provide agencies with
information regarding the effects of alternative decisions-making techniques. Alternative design
approaches may also lead to easier implementation at the local level.
The research could be used to change agency-wide policies and
guidelines, which would be used by state DOT staff who are planning and
designing new roadways and roadways undergoing reconstruction. Pilot testing,
training and workshops would help further implementation.
$550,000
24 months
Jennifer Dill, Portland State University
Christopher Monsere, Portland State University
Jeremy Chrzan, Toole Design Group
AASHTO Council on Active Transportation
Federal Highway Administration (2017). Start-up Guide:
Performance-Based Practical Design, FHWA-HIF-17-026, March 1, 2017. https://www.fhwa.dot.gov/design/pbpd/
Hagedorn, Hau (2020), Policy Implications of ORS 366.514 –
The Oregon Bike Bill, eMPA Capstone project, Portland State University.
Mooney, Robert (2015). Performance-Based Practical Design:
Maximizing System Performance by Rethinking Design Decisions. ITE Journal,
85 (12): 38-42.
Schultheiss, W., Sanders, R. L., & Toole, J. (2018). A
historical perspective on the AASHTO guide for the development of bicycle
facilities and the impact of the vehicular cycling movement. Transportation
Research Record, 2672(13), 38-49.
Yannis, G., Kopsacheili, A., Dragomanovits, A., &
Petraki, V. (2020). State-of-the-art review on multi-criteria decision-making
in the transport sector. Journal of Traffic and Transportation Engineering
(English edition), 7(4): 413-431.