Traffic injuries go down as bicycling goes up

Bicycling has become New York City’s fastest-growing mode of transportation, and one of the fastest-growing in the nation as well.
Figures from Transportation Alternatives, an advocacy group in New York, show that in 2009 the city had 201,000 people cycling every day. This was New York’s fourth straight year of double-digit growth in cycling, said Paul Steely White, Transportation Alternatives’ executive director.

The rise came on top of a doubling in the number of New York cyclists between 1985 and 2005, as measured by the city’s Department of Transportation. The number of people commuting into the core of Manhattan by bike tripled between 2000 and 2009. The number of New Yorkers identifying themselves as bike commuters grew by 70 percent from 2000 to 2008, census data show. In 1998, cyclists in the city were estimated to number only 98,000.

Nationally, biking trips jumped from 1.7 billion in 1990 to 4 billion in 2009, according to the National Bicycling & Walking Study of the US Department of Transportation.

You might think this would result in more cyclist traffic accidents. But according to Transportation Alternatives, injuries to cyclists in New York actually dropped — from 5,025 in 1998 to 2,916 in 2008 to 2,730 in 2009. Some of the drop might be attributable to added bike lanes and improvements to previously dangerous intersections.

But the main reason seems to be a phenomenon that public health consultant Peter Jacobsen identified in an impressively researched article, “Safety in numbers,” in the journal Injury Prevention in 2003. Jacobsen found that when bicyclists (or pedestrians) become numerous, motorists adjust their behavior. They drive more carefully. Policies that increase the number of people walking or biking pay off in greater safety, he concluded.