City data seem to bear out idea that seeing more bikers leads drivers to watch for them.
The more people bike in Minneapolis, the safer they seem to be.
What's new? Recently crunched city data show the reported cyclist-motorist accident rate dropping as the number of bike commuters grows. For 2008, the most recent year for which complete data were available, the crash rate was one-quarter that of 10 years earlier. Moreover, a trend line shows a steady decrease in the crash rate even as the number of commuting cyclists more than doubled.
There are some limits to the Minneapolis data. The number of cyclists is taken from the number of people ages 16 or older who tell census takers that their main transportation to work the previous week was a bike. That figure grew from about 3,000 in the 1990s to about 8,000 in 2008. It excludes infrequent commuters and recreational bikers. Meanwhile, the number of crashes involved only those reported to the city between bikers and motorists, which remain at or below 1990s levels. That means the crash rate has fallen sharply while commuting bikers are on the rise.
Is this happening elsewhere? It squares with a 2003 analysis on biking and walking in two California cities. "A person is less likely to collide with a person walking or biking if more people walk or bicycle," public health consultant Peter Jacobsen wrote in the journal Injury Prevention.
Why is this happening? Familiarity breeds safety, one city bike advocate believes. "People are so used to seeing bicyclists -- love them or hate -- and they don't want to hit them," said Shaun Murphy, coordinator of the city's nonmotorized transportation program. Murphy said the map of hot spots for bike-car accidents doesn't show major issues around the University of Minnesota because drivers there are so used to watching for bikes.
Do bike lanes help? Murphy also credits more bike lanes. Bike lanes can benefit pedestrians as well. When bike lanes were striped on Riverside Avenue, for example, the number of bikers riding on sidewalks dropped by 87 percent, said Hilary Reeves, a spokeswoman at Transit for Livable Communities, which manages a federal grant to promote biking and walking in the Twin Cities.
How many bike crashes are there? The city records 200 to 300 bike-vehicle crashes annually. Preliminary statewide numbers show that nine bikers were killed in vehicle crashes in 2010, with 926 crashes reported. All but one of the fatalities and the preponderance of those injured last year were male, while close to half were between ages 10 and 24.
Steve Brandt • 612-673-4438