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Safety Effectiveness Evaluation of Innovative On-Street Bikeway Designs (OR) Development of Crash Modification Factors and Design Guidelines for Innovative On-Street Bikeway Designs


In 2015, over 1,000 bicyclists died and there were almost 467,000 bicycle-related injuries in the U.S. (1). According to statistics obtained from Center for Disease Control and Prevention, these crashes have resulted in lifetime medical costs and productivity losses of over $10 billion. In an effort to reduce the bicycle-related crashes around the country, a growing number of innovative on-street bikeway designs have been installed. New on-street bikeway designs include but are not limited to protected intersections, protected bike lanes, two-way cycle tracks, two stage turn queue boxes, buffered bicycle lanes, advisory bike lanes, etc. A number of studies conducted in the U.S., Europe, Canada, and Australia show that new bicycling infrastructure can increase the exposure, and result in modal shift among the road users. Consequently, the increasing exposure could increase the frequency and severity of bicycle related crashes. Research is therefore needed to better understand the safety implications of the new on-street bikeway designs along road segments and intersections for the bicyclists. In addition, the design details for the new facilities need to be better defined and standardized. There is no specific design guidance relating to these facilities, thus the research is needed to develop the design guidelines for installing these treatments.


The objective of the proposed study is two-fold: (1) Conduct safety evaluation of new on-street bicycle facility designs and develop Crash Modification Factors (CMF); (2) Provide guidance on design of the facilities studied.

Related Research:

Buffered bike lanes can increase a bicyclist’s perceived safety and comfort which may increase more bicyclists to ride on the roadway (2). Designing roads segments and intersections to accommodate vulnerable road users can slow traffic down and help reduce crashes. While improved bicycle infrastructure can be a factor for crash reductions, driver speed and a bicyclists lane positioning is a key factor for a higher driver yield rate (3). On-street bikeway designs created to encourage bicyclists to take the full lane and ride with traffic safely is an ideal design. For the longer road segments and near intersections, bicycle crashes were significantly more likely to be fatal when they involved motorists traveling straight, were along roadways between intersections, and involved motorists traveling in the same direction as the bicyclist (4, 5). As more facilities are installed, future research could evaluate a design across various volume thresholds. Future work to evaluate the designs should include actual crash data. The most likely benefit will come from comparing intersection designs on protected bikeways with traditional bike lanes at intersections (7).

  1. Center for Disease Control and Prevention. Bicycle Safety. https://www.cdc.gov/motorvehiclesafety/bicycle/index.html

  2. Influence of Bike Lane Buffer Types on Perceived Comfort and Safety of Bicyclists and Potential Bicyclists Nathan McNeil, Christopher M. Monsere, and Jennifer D Volume 2520 DOI:10.3141/2520-15

  3. When Do Drivers Yield to Cyclists at Unsignalized Roundabouts? Empirical Evidence and Behavioral Analysis Ary P. Silvano, Xiaoliang Ma, and Haris N. Koutsopoulos https://doi.org/10.3141/2520-04

  4. Enhancing Cycling Safety at Signalized Intersections Analysis of Observed Behavior Jeffrey M. Casello, Adam Fraser, Alex Mereu, and Pedram Fard Transportation Research Record: Journal of the Transportation Research Board, No. 2662, 2017, pp. 59–66. http://dx.doi.org/10.3141/2662-07.

  5. Level-of-Service Model for Protected Bike Lanes Nick Foster, Christopher M. Monsere, Jennifer Dill, and Kelly Clifton Transportation Research Record: Journal of the Transportation Research Board, No. 2520, Transportation Research Board, Washington, D.C., 2015, pp. 90–99. DOI: 10.3141/2520-11.

  6. Application of the Location–Movement Classification Method for Pedestrian and Bicycle Crash Typing Robert J. Schneider and Joseph Stefanich Transportation Research Record: Journal of the Transportation Research Board, No. 2601, Transportation Research Board, Washington, D.C., 2016, pp. 72–83. DOI: 10.3141/2601-09

  7. User Behavior and Perceptions at Intersections with Turning and Mixing Zones on Protected Bike Lanes Christopher M. Monsere, Nick Foster, Jennifer Dill, and Nathan McNeil Transportation Research Record: Journal of the Transportation Research Board, No. 2520, Transportation Research Board, Washington, D.C., 2015, pp. 112–122. DOI: 10.3141/2520-13.


The project tasks should consist of:

Phase I:

Task 1 – Review of the existing design guidelines from practicing states and cities to identify the list of innovative bicycle (and pedestrian) facility designs which are new and yet common enough that they can be studied. This task will focus on the revision of geometrics, safety, maintenance issues, comfort, impact to traffic, pedestrian crossing distance and waiting locations.

Task 2 – Identify the list of implementing agencies and city MPOs, and assess the readily available safety databases for the evaluation of the newly implemented bikeway designs. Develop a data collection plan for those design that do not have enough after data.

Task 3 – Prepare a Phase II work plan indicating the list of the CMFs that will be developed; available datasets; and the potential statistical approaches. For conducting the statistical analysis, the project team will coordinate with the NCHRP 17-84 project team and use the Safety Performance Functions (SPF) developed in the aforementioned project. In case of limited after period crash data propose an additional list of analytical methods (Empirical Bayes, Full Bayesian, Propensity Score Matching, etc.) that can help to overcome the data limitations.

Task 4 – Prepare an interim report documenting the literature review, datasets, and proposed work plan.

Phase II:

Task 5 – Execute work plan developed in Task 4 and approved by NCHRP panel.

Task 6 – _Conduct the statistical analysis _using the proposed methodologies that have been approved by the NCHRP panel.

Task 7 – _Prepare final deliverables and guidelines. _The research team will develop a final project guidelines documenting the research results and the guidelines for the studied on-street bicycle facilities.


The TRB Standing Committees on Bicycle Transportation, Highway Safety Performance, and Geometric Design have identified this research as a high priority. This research will have significant influence on the safety implications of new on-street bikeway designs. Currently there are no CMFs associated with the bikeway designs included in this research need statement.

The expected products of the research need statement are the CMFs for on-street bicycle facilities and specific guidance to inform roadway and intersection design. This study will enforce the results of the NCHRP 17-84 study. The results of the study will be included in the AASHTO Highway Safety Manual (HSM) and Green Book publications. Another expected product of this project is the design guidelines document describing the standards for implementing the bikeway designs. Roadway designers and planners are eager for information on how to design roadways and intersections for use by multiple modes, including motor vehicles and bicycles. This project would provide important information on how to accomplish those objectives.

Sponsoring Committee:AFB10, Geometric Design
Research Period:24 - 36 months
Research Priority:High
RNS Developer:Jason Jackman – University of South Florida. Krista Nordback – University of North Carolina. Bahar Dadashova – Texas A&M Transportation Institute. Rebecca Sanders – Toole Design Group.
Date Posted:09/21/2018
Date Modified:12/31/2018
Index Terms:Bikeways, Highway safety, Bicycle crashes, Design standards, Crash modification factors,
Cosponsoring Committees:ANB25, Highway Safety Performance; ANF20, Bicycle Transportation
Pedestrians and Bicyclists
Operations and Traffic Management
Safety and Human Factors

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