Safety Effects of Separated Bikeways

Title: Safety Evaluation of Separated Bikeway Designs

Problem: Separated bikeways (also known as cycle tracks) are bikeways within or adjacent to the roadway and separated from moving traffic by curbs, parking lanes, striped buffers, or other barriers. They do not include multiuse pathways, which are open to a variety of other non-motorized users and are typically located outside of roadway rights-of-way. Separated bikeways are increasingly popular throughout the United States, with recently installed facilities in Portland, Oregon; New York, New York; Washington, DC; Cambridge, Massachusetts; and other locations, and numerous state and local departments of transportation exploring the potential for additional facilities.¹

Many transportation agencies view these facilities as an opportunity to attract higher volumes of cyclists, and studies show a preference for separated bikeways among both current and potential cyclists.^2,3,4

While separated bikeways are popular with cyclists, only limited data are available on the safety outcomes of separated bikeways. With over 600 annual cyclist fatalities in the United States, improving cyclist safety is a critical outcome for bicycle facility design, suggesting the need for objective research on the safety implications of separated bikeways.

Published research on the safety of separated bikeways in the United States is sparse; however, research from Europe and Canada suggest that separated bikeways may improve cyclist safety compared on on-street facilities. For instance, recent research of separated bikeways in Montreal found that the risk of injury for riders in cycle tracks was less than those riding in streets. In addition, over twice as many cyclists were recorded using cycle tracks as compared to the alternative, typically parallel, bike routes used for comparison in the study, suggesting a preference for separated bikeways.⁵

The experiences of northern European countries, where separated bikeways are widely used, show similar results, with significantly lower bicycle crash rates and higher rates of cycling than observed in the United States.^6,7,8 A recent study focus on the safety effects of Copenhagens cycle track found overall positive results as well for separated bikeways, though cyclist safety at intersections was negatively impacted.⁹

As documented by international experience, separated bikeways have the potential to create both safe and comfortable environments that can help transportation agencies meet their goals to provide improved transportation options. However, quantitative research on the safety of separated bikeways within an American is needed to provide designers with the guidance necessary to ensure that future bike facilities are as safe as possible.

Objectives: The proposed research will quantify the safety characteristics of separated bikeways in the US. To accomplish this, the research must:

1. identify existing separated bikeway treatments on roadways in the US;

2. review the experience of different types of separated bikeways in North America with respect to crash and injury history;

3. identify all prevalent crash and conflict types, including motor vehicle/bicycle, bicycle/bicycle, and bicycle/pedestrian, associated with each type of separated bikeway at midblock, driveway, on-street parking, and at controlled and uncontrolled intersection locations;

4. isolate the physical and human factor causes for the various crash types identified;

5. identify effective designs to address the operational issues identified;

6. identify effective designs to address the crash factors identified;

7. codify designs and guidelines that are useful for designers for a variety of separated bikeway types under a range of conditions and roadway types;

8. determine which, if any, separated bikeway design features offer acceptable levels of safety based on the results of the research;

9. identify additional research needs.

The investigation should consider a range of separated bikeways immediately adjacent to roadways, including, but not limited to, one-way and two-way bikeways, bike lanes separated from motor vehicle traffic by different types of barriers or by parking lanes, and paths raised to sidewalk or near sidewalk level. It should consider applications on streets with and without parallel parking, and both signalized and unsignalized intersections. The impact of various design treatments should also be examined to the extent possible, including the impacts of:

signal phasing options to separate cyclists and turning motorists;;intersection approach treatments;

removal of parking to improve sightlines, especially at intersections;

access management and driveway frequency;

signs and pavement marking at intersections, including colored pavement;

advanced stop lines (bike boxes) to allow bicyclists to queue ahead of motorists at signalized intersections; and

alternative methods to accommodate bicycle left-turns

A possible outcome of the research would be information useful for the development of guidance that could be included in, supplement, or update the revised AASHTO Guide for the Development of Bicycle Facilities, which is currently in the process of AASHTO balloting. One of the critical issues identified for this guide is the lack of research on various separated bikeway designs in the US. Research results could also be used to update other guidance documents, such as the National Association of City Transportation Officials Urban Bikeway Design Guide, or influence updates to the Federal Highway Administrations Manual on Uniform Traffic Control Devices. Other possible outcomes are a greater understanding of the safety, efficiency, connectivity, and maintainability issues associated with some separated bikeway designs, and the identification of additional research needs.

Key Words: bicycle, safety, separated bikeway, bike facility, Traffic Engineering

Related Work: A number of cities in the United States (e.g. New York City, Portland, Washington, D.C.) have recently installed one-way and two-way separated bikeways on roadways with the intent to improve safety. While several of these treatments have been employed and studied in Western European countries and Canada, little research currently exists on the effectiveness of these facilities in the US. Research on the use and effectiveness of these facilities in the US is inconsistent and scattered, and should be actively pursued to determine whether and to what extent these treatments benefit bicyclists.

Urgency/Priority: This research has high priority. In addition to providing safety guidance to practitioners on the effectiveness of separated bikeways, this research would provide additional measures for determining the safety benefits or drawbacks for various treatments.

Jurisdictions throughout the country are searching for quantifiable solutions for bicycle safety issues at intersections and along roadways.

Cost: $350,000

User Community: state departments of transportation (DOTs), local governments, traffic engineers, roadway designers, traffic operations and maintenance personnel, pavement markings designers, bicycle facility planners

Implementation: This research would influence the design and installation of separated bikeways on new roadways, reconstruction projects, and resurfacings related to the design of urban roadways and intersections.

Effectiveness: Execution and implementation of this research would provide substantial knowledge on the safety of separated bikeways. Separated bikeways have the potentially improve safety for cyclists, but without US research in this area it is difficult to determine the effectiveness of these facilities.

References

1. Urban Bikeway Design Guide, National Association of City Transportation Officials, nacto.org/cities-for-cycling/design-guide/, accessed March 2011.

2. Dill, J. and K. Voros. (2007) Factors Affecting Bicycling Demand, Initial Survey Findings from the Portland, Oregon, Region. Transportation Research Record. 2031: 9-17.

3. Sener, I.N., N. Eluru, and C.R. Bhat. (2009) An Analysis of Bicycle Route Choice Preferences in Texas, US. Transportation. 36(5): 511-539.

4. Garrard J, Rose G, Lo SK. Promoting transportation cycling for women: the role of bicycle infrastructure. Prev Med 2008; 46:55e9.

5. Lusk, A., P. Furth, P. Morency, L. Miranda-Moreno, W. Willett, and J. Dennerlein (2011). Risk of injury for bicycling on cycle tracks versus in the street. Injury Prevention 2011;17:131-135.

6. Pucher J and R Buehler (2007) Cycling for Everyone: Lessons from Europe. Transportation Research Record: Journal of the Transportation Research Board, No. 2074, November 2008, pp. 58-65

7. Pucher J, Dijkstra L. (2003). Promoting Safe Walking and Cycling to Improve Public Health: Lessons from the Netherlands and Germany. Am J Public Health, Vol. 93, pp. 15091516.

8. Pucher, J, Dill, J, and Handy, S, Infrastructure, Programs and Policies to Increase Bicycling: An International Review, prepared for the Active Living Research Program of the Robert Wood Johnson Foundation, and tentatively scheduled for publication in Preventative Medicine, Vol. 48, No. 2, February 2010.

9. Jensen S. Bicycle tracks and lanes: a before-and-after study. Transportation Research Board 87th Annual Meeting, 2008-1-13 to 2008-1-17. Washington, DC. 2008:15.