That the most important factor in urban bicycling safety is the presence of other cyclists. When there are lots of cyclists, car drivers expect to see them, watch for them, and drive carefully. When there aren’t, car drivers don’t expect to see them, feel entitled to own the road, and don’t drive carefully.

A study from New York firm nonprofit Transportation Alternatives that was posted to Streetsblog shows that safety in numbers has manifested itself in a big way in that city.

As more and more New Yorkers pick up bicycling, fewer and fewer bicyclists are getting hurt or killed. It’s not just fewer per capita; the absolute number has declined. It’s pretty compelling:

Graph from Transportation Alternatives, via Streetsblog.

Update by David: For comparison, here’s a graph Streetsblog posted showing the growth in cycling. There’s some debate over exactly how many cyclists there are, but no dispute that it’s growing.

Dan Malouff is a transportation planner for Arlington and an adjunct professor at George Washington University. He has a degree in urban planning from the University of Colorado and lives in Trinidad, DC. He runs BeyondDC and contributes to the Washington Post. Dan blogs to express personal views, and does not take part in GGWash's political endorsement decisions.