Bicycle Collisions

The following is an excerpt from the Metro Bicycle Master Plan (2009), which was based primarily on research found in “Bicycle Collisions in Johnson County,” by P. Knapp, S. Knoploh-Odole, L. Levy, J. Rosenberg, and S. Snyder (University of Iowa Department of Urban & Regional Planning, 2008).

This map illustrates the locations of bicycle collisions.

Analysis of the 273 documented on-street collisions in Johnson County between 2001 and 2007 revealed several trends. First, more than half of all on-street collisions involved cyclists 22 years old or younger, which suggests that education efforts could be focused on this demographic. Second, of the on-street collisions where safety equipment was checked, only 25 percent of cyclists were wearing helmets (not required by law) and none had lights on their bicycles (required by state and local code).

Of the bike collisions that occur on-street, a substantial number of collisions occur in the fall when students return to school. These statistics suggest that educational outreach should be targeted toward young adults and that enhanced education of bike light and reflector laws could reduce collision rates.

Not surprisingly, streets with high numbers of cyclists traveling with medium to high volumes of vehicles tend to experience higher rates of bike collisions. Burlington Street, Gilbert Street, and Dodge Street are the most common corridors with collisions. On-street pavement markings, such as bike lanes and sharrows, are a common tool on roadways where traffic volumes and speeds lead to conflicts between vehicles and bicycles.

Of collisions that occur on-road, bicycle collisions occur more frequently during the week (84 percent), rather than on weekend days.

To limit collisions with bicycles, cities must realize that no “silver bullet” solution exists. The skill levels of cyclists vary dramatically, from the experienced cyclists who ride daily and prefer safe, direct routes to inexperienced youth who ride to school, parks, and close-to-home destinations. Depending on their experience, cyclists use various combinations of bikeways to reach their destinations, and therefore no one facility will meet all cyclists’ needs.

However, a large segment of the cycling population fall somewhere in-between these two extremes, including many more potential cyclists who do not ride regularly now, but would likely do so if a safer system existed.

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