Bicycle sidepaths: crash risks and liability exposure

Evidence from the research literature

The evidence that bicycling on sidewalks and similar facilities is more hazardous than bicycling on streets is overwhelming. Need to see that evidence? Here are some graphs, and links to studies posted on the Internet on this site and others:

Adult Bicyclists in the U.S. by Dr. William Moritz. Relative danger index 24.8 times as high for sidewalk riding as for major street without bicycle facilities. (Data include all crashes, not just car-bike collisions). The population was avid adult recreational and utility cyclists. The following graph by Martin Pion summarizes the results for different facility types.

A Survey of North American Bicycle Commuters by Dr. William Moritz Relative danger index 5.32 times as high on "other" facilities (mostly sidewalks) as on average of all facilities (mostly streets). Data include all crashes, not just car-bike collisions. Lower ratio than in previous study probably related to typically lower speed and overall higher crash rate of average commuters compared with avid cyclists.

The Risks of Cycling by Dr. Eero Pasanen, Helsinki, Finland. Small samples, but results consistent with other studies:

Higher car-bike collision rate for one-way sidepaths compared with streets, even though pedestrians are prohibited from the sidepaths. Higher rate yet on sidewalks. Rate on sidepaths 4 times as high as on paths away from streets.

2.5 times as high rate when crossing intersection from sidewalk compared with street, 2.9 times as high when crossing from path.

Extremely high rate of car-bike collisions with bicyclists crossing intersection on the left sidepath.

1987 study by the University of Lund, Sweden. (summarized in a conference report, with an explanation of the diagram below). 11.9 times the risk of car-bike crashes for bicyclists riding on a left sidepath, and 3.4 times for bicyclists on the right sidepath, compared with bicyclists riding in the normal position on the road.

Alan Wachtel and Diana Lewiston, Risk Factors for Bicycle-Motor Vehicle Collisions at Intersections (ITE Journal, September 1994). Car-bike collision rate 1.8 times as high for sidewalk riding as for streets on average, and higher for all categories of cyclists.

Sidewalk Bicycle Safety Issues , by Lisa Aultman-Hall and Michael F. Adams Jr. Bicycle crash rate 6 to 10 times as high on sidewalks as on streets in Toronto. (PDF document. See page 4.)

Toronto Bicycle Commuter Safety Rates, by Lisa Aultman-Hall and M. Georgina Kaltenecker. 4 times as high injury accident rate on sidewalks as on streets (PDF document. See table 5, page 19).

A survey of research on the crash rates of streets, bicycle paths and sidewalks is available on the Internet on John Franklin's site.

A summary of the topic of bicycle accident types and prevention is to be found in the books Effective Cycling and Bicycle Transportation, by John Forester, published by MIT Press.

Liability Aspects

The paper Liability Aspects of Bicycle Environments: Bicycle Facilities and Roads , by three notable experts on bicycle transportation, Alex Sorton, P.E., Tom Walsh, P.E. and John Williams was presented at the Institute of Traffic Engineers 1990 Annual Meeting and specifically recommends against sidewalks and sidepaths as bicycle facilities. Here are extracts from that paper: