The number of cycling fatalities in the United States has been on an upward trend. Nationwide, cycling deaths rose from 621 in 2010 to 722 in 2012. This trend correlates with the increase in the number of people commuting by bicycle. However, interestingly, a research report by the OECD actually shows that in a country where more people cycle, the cycling fatality rate tends to be lower.
This "safety in numbers" phenomenon is easy to understand — the more people cycling means drivers are more aware of cyclists. In congested urban areas, solo cyclists are more prone to accidents and injuries. In countries like the Netherlands and Denmark, where people cycle an average of 864 km and 513 km per year respectively, the fatality rate per billion kilometers cycled is 10.7 and 14.6 respectively.
In comparison, the average annual cycling distance in the United States is just 47 km. Yet, the fatality rate per billion kilometers cycled is as high as 44, indicating that fewer cyclists mean a higher likelihood of traffic accidents and fatalities. Equally important, in Denmark and the Netherlands, cycling has been a way of life for decades, and both countries also have well-developed infrastructure to ensure cyclist safety.
So why does the rise in cycling fatalities in the United States coincide with the increase in cycling commuters? The OECD report also points out that the idea of "safety in numbers" involves a certain degree of uncertainty. Both cyclists and drivers need time to adapt to each other’s presence. A rapid increase in the number of bicycles on the road may lead to more traffic accidents in the short term, until the "safety in numbers" effect takes hold over a longer period.