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The National Academies

NCHRP 03-133 [Active]

Traffic Signal Design and Operations Strategies for Non-Motorized Users

  Project Data
Funds: $500,000
Staff Responsibility: C. Crichton-Sumners
Research Agency: Kittelson & Associates
Principal Investigator: Kevin Lee
Effective Date: 4/30/2018
Completion Date: 4/29/2020
Comments: Research in progress. The interim report has been delivered and accepted.

BACKGROUND
 
There is increased interest by state and local transportation agencies as well as by the general public in promoting active and sustainable transportation modes such as bicycling and walking as a means to alleviate congestion, lower emission levels, and improve personal health. According to the American Community Survey conducted by the U.S. Census Bureau, between 2007 and 2016 the average percentage of commuters who walk or bike increased from 2.5 to 2.8 and from 0.4 to 0.6 respectively (U.S. Census Bureau, Department of Commerce 2016).  The 2009 National Household Travel Survey (NHTS) estimated 41 billion walking trips per year, accounting for 10.4% of all trips undertaken and bicycle trips increased from 0.7% of total trips in 1995 to 1.0% in 2009 (Federal Highway Administration 2011).  These non-motorized trips, made by users of all ages and abilities, tend to be short and traverse signalized intersections in urban and rural settings. Signal timing is typically optimized for motor vehicles and delays at signalized intersections tend to affect pedestrians disproportionately compared to auto trips. The Highway Capacity Manual (HCM) states that delays greater than 30 seconds are associated with increased frustration and risky behaviors leading to pedestrian noncompliance which may lead to their injury or death. The delay experienced by non-motorized users at crossings may be due to many factors, including the traditional focus on prioritizing vehicular movement, geometric features/constraints, or other infrastructure related limitations at signalized intersections.
 
Research on pedestrian safety at intersections has focused on lack of driver yielding, pedestrian noncompliance, and pedestrian visibility. This has resulted in the emergence of countermeasures such as countdown pedestrian signals, enhanced beacons, leading pedestrian intervals, and exclusive pedestrian phasing. Although limited, bicycle safety research has focused on improving the safety of bicyclists in the traffic stream, focusing on design treatments rather than intersection operations with little research available on signal timing. Despite the availability of safety measures, due to slow technology transfer and assimilation or misapplication, current national trends show an increase in fatalities and injuries for these non-motorized users.

As the number of bicyclists and pedestrians increases, safety and operations at intersections remain a serious concern. Consequently, more comprehensive guidance related signal design and operations strategies is needed.

OBJECTIVES
 
The objectives of this research are to (1) identify and evaluate a broad range of current international and national practices for signal design and operations strategies for non-motorized users including vulnerable road users with disabilities; (2) identify gaps in the state of practice on signalized intersections with multimodal specific infrastructure and intersections with varied geometric designs (e.g., signalized path crossings, diverging diamond interchanges, continuous flow intersections, etc.); (3) develop guidance for traffic signal design and operations strategies that will address the needs of non-motorized users and increase their respective multimodal connectivity; (4) develop a means to convey how to best incorporate findings to a wide range of stakeholders including those with visual impairments and other disabilities; (5) recommend germane language for inclusion in future updates to guidance documents (e.g., the AASHTO design manual, the Traffic Signal Timing Manual and specifications); and (6) identify opportunities for future research.
 
RESEARCH PLAN
 
The NCHRP is seeking the insights of proposers on how best to achieve the research objective. Proposers are expected to describe research plans that can realistically be accomplished within the constraints of available funds and contract time. Proposals must present the proposers' current thinking in sufficient detail to demonstrate their understanding of the issues and the soundness of their approach to meeting the research objective.
 
The research plan should: (1) include a kick-off teleconference with the research team and NCHRP convened within 1 month of the contract’s execution; (2) address the manner in which the proposer intends to use the developed information to satisfy the project objectives; (3) be divided logically into detailed tasks that are necessary to fulfill the research objective and include appropriate milestones and interim deliverables; (4) include information gathering tasks; and (5) incorporate opportunities for the project panel to review the progress and provide feedback.
 
One anticipated outcome of the research will be the creation of a toolbox relevant to a broad range of stakeholders. It will include guidance for practitioners that integrates both proven and innovative traffic signal design and operations strategies to help improve the safety and efficiency of non-motorized users of all ages and abilities and be appropriate for varied types of signalized intersections.
 
The research plan should at least include the following activities:

  • Review literature and identify gaps and current practices in signal design and operations strategies and categorize needs of non-motorized users. Include innovations, emerging technologies, deficiencies, and the findings of research attempting to address those needs. Qualitatively evaluate the impacts of the identified strategies at signalized intersections for non-motorized users.
  • Interface with city, county, and state transportation officials to identify traditional non-motorized signal design and operations challenges when addressing these users at both rural and urban intersections with infrastructure specific to non-motorized users. This may be accomplished via web-conference and shall be convened with selected agency officials to gather feedback early enough to inform the work plan.
  • Identify, propose, test, and analyze select design and operations strategies at signalized intersections and quantify safety, operations, and other performance-based impacts.
  • Characterize system components (e.g., level of detection, type of controller or controller software/timing parameters, ITS architecture, type of communication system, etc.) necessary for successful deployment of these strategies. Identify and categorize levels of maintenance, support, and expertise that a managing agency would need in order to make effective use of these strategies.
  • Develop a tiered set of goals and objectives-based strategies and associated performance measures for practitioners across a spectrum of contexts (e.g., enforcement, traffic demand, signal timing and coordination, network configuration, user mix, budget constraints, and organizational capabilities). Strategies may be applicable to conventional traffic signals and/or innovative technologies such as Rectangular Rapid Flashing Beacons (RRFB), pedestrian hybrid beacon, etc.
  • Develop a framework and design materials to facilitate public outreach and education. Reproduction costs associated with outreach and education materials will be borne by NCHRP.
 
Deliverables should include: (1) an agency outreach and interface summary; (2) a stand-alone tool box that contains (a) guidance on traffic signal design and operations strategies for non-motorized users in signalized intersections; and (b) a conceptual framework and set of training materials to facilitate public outreach and education for use by practitioners to encourage widespread use; (3) prioritized recommendations for future research; (4) a final report documenting the entire research effort; (5) a PowerPoint-style presentation describing the background, objectives, research approach, findings, and conclusions; and (6) a stand-alone technical memorandum titled “Implementation of Research Findings and Products”.
Proposers may recommend additional deliverables to support the project objective.

STATUS: Proposals were received in response to the RFP. The panel met in December to select a contractor to perform the work.

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