As the number of bicyclists on Philadelphia streets has risen, cyclists and city officials have seen a counterintuitive result: The number of bike crashes and deaths has declined.
This “safety in numbers” phenomenon has been documented elsewhere, and safety experts believe it is because motorists become more alert to cyclists when there are more of them.
Since 2002, the number of cyclists on many Center City streets has more than doubled, according to tallies at key intersections, and the percentage of bike commuters has also doubled. In 2002, there were six bicyclists killed in accidents with motor vehicles; last year, there were two such deaths.
Traffic crashes involving bikes in Philadelphia have fallen from a high of 1,040 in 1998 to 553 in 2010.
“Where cars expect to find bicyclists and pedestrians, drivers are more cognizant of cyclists and pedestrians,” said Alex Doty, executive director of the Bicycle Coalition of Greater Philadelphia. He cited a study in Portland, Ore., that found a doubling of the number of bicycles reduced the crash risk by one-third.
“I know I get better treatment now than I did 10 years ago, or even five years ago,” Doty said. “Drivers have a better idea what to do. Though there is still quite a bit of room for improvement.”
The correlation was reported in 2003 by the medical journal Injury Prevention, when it published what it called an “unexpected result” of a safety study: The likelihood of a cyclist or pedestrian being hit by a car “varies inversely with the amount of walking or bicycling.”
The journal’s study concluded that “policies that increase the numbers of people walking and bicycling appear to be an effective route to improving the safety of people walking and bicycling.”
In Philadelphia, the Nutter administration has created dozens of bike lanes and bike routes, trying to carve out more space for cyclists in a city not known for its bicycle bonhomie.
The safety in numbers phenomenon “is really playing out” in the city, said Stephen Buckley, director of policy and planning in the mayor’s Office of Transportation and Utilities. The city has about 220 miles of bike lanes, he said, and the administration hopes to increase that to about 300 miles. [Full story ….]