The logic seems simple. More bikes on city streets means more potential for bike accidents in the city. The twist is that more bikes may actually make the streets safer for bikers on average.
In the wake of Citi Bike’s recent launch in New York City, the idea seems counterintuitive. But as reported in The New York Times’ Well Blog, the presence of more bikes on the streets may make drivers more aware of the cyclists around them. Adding more bike lanes to accommodate them may help even further.
Beyond that, bike share programs also seem to have a positive impact on public health and morality rates in general. A 2011 study of Barcelona's program asserted that a general increase in physical activity, along with less traffic congestion and air pollution, helped prevent 12 deaths in that city per year. A 2009 report by New York City’s Department of City Planning concluded that although the rate of accidents typically goes up in the first year of a bike share’s launch, the number of bikers increases by an even higher percentage, bringing down the rate of accidents per biker.
This pattern was seen in 2007 when Paris introduced its bike share Vélib’. Bike use increased 24 percent in the French capital from the previous year. Accidents increased only 7 percent.