Identifying risk factors for on-road commuter cyclists

 
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In September 2013, California governnor Jerry Brown signed a law requiring that motorists give cyclists at least 3 feet of clearance when passing. While this represents a victory for the state’s cycling community, previous research indicates that such laws aren’t entirely effective: A 2012 study in Accident Analysis & Prevention found that a similar law in Baltimore, Maryland, wasn’t entirely effective: It found that after the law came into effect, 17% of drivers continued to pass within 3 feet of cyclists. The researchers suggest two possible solutions: “Interventions and strategic education campaigns” as well as the construction of bicycle-specific infrastructure.

Whatever its effectiveness, the California law is in part a recognition that bicycle commutering is becoming more common. Once limited to cities such as Portland, Oregon, cyclists become an increasingly familiar sight across the United States. In a survey by the American League of Bicycles, other top cities include Minneapolis, Seattle, San Francisco, New Orleans and Honolulu. This trend has been encouraged by new bike-sharing systems, “complete streets” initiatives and legal measures to better protect cyclists.

Despite such gains, bicycle commuting isn’t without risk, particularly when cyclists must share streets designed to maximize automotive speed and traffic volume. A 2010 study by Monash University, Australia, “Identifying Risk Factors for On-road Commuter Cyclists,” sought to better understand risk factors by equipping cyclists with helmet-mounted cameras over a four-week period.

More than 127 hours of data were gathered and the behavior of cyclists and drivers analyzed. Fifty-four car-cyclist interactions were recorded and classified by severity. Two were collisions, 6 near-collisions and 46 were incidents. The results include:

  • Prior to events, 88.9% of cyclists traveled in a safe and legal manner.
  • Vehicle drivers were at fault in 87% of the events, with more than 83% of drivers showing no post-event reaction.
  • The most frequent event was caused by drivers suddenly changing lanes, 40.7%.
  • 70.3% of events occurred at an intersection or intersection-related locations.
  • Cyclists who frequently looked over their shoulders had the highest situational awareness and the greatest ability to avoid collisions or near-collisions with cars.
  • The lack of bicycle-specific infrastructure was a significant risk factor: “A bicycle lane was present in less than half of the observed events and across all event severities. The cycling lanes observed were disjointed and often ended abruptly, frequently where the road narrowed, without a viable option for the cyclist.

The authors suggest that strategies be implemented to increase drivers’ awareness of cyclists, particularly when turning or changing lanes. In addition, they highlight the importance of infrastructure that can better protect cyclists: “Greater consistency in cycling facility design is needed,” they state. “A review of existing cycling facilities is also required to improve continuity and provide intuitive end-point options to ensure the road space afforded to cyclists is identifiable.”

Keywords: bicycling, bicycle, bikes, cycling, cars, safety, bikeshare

    Writer: | Last updated: May 23, 2013

    Citation: Johnson, Marilyn; et al. "Naturalistic Cycling Study: Identifying Risk Factors for On-road Commuter Cyclists," Annals of Advances in Automotive Medicine January 2010, Vol. 54, 275-283.
     

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