One Chart Brilliantly Sums Up Citi Bike’s Safety Record

Courtesy of GIS specialist Tom Swanson, this graphic contains the best evidence yet that Citi Bike has not led to an increase in bicyclist injuries.

Using crash information scraped from NYPD PDFs by freelance web developer John Krauss, Swanson was able to map which bicyclist injuries occurred inside the Citi Bike service area. Then he charted those injuries as a percentage of all cyclist injuries in the city. If Citi Bike was leading to a significant increase in injuries to cyclists, you would expect to see the percentage of cyclist injuries in the service area rise after bike-share launched at the end of May 2013.

Instead, Swanson's chart shows that the share of injuries in the service area is holding steady. Compared to the same months in previous years, there has been almost no deviation from the pre-bike-share state of affairs. We already knew that very few people have been injured riding Citi Bike. Swanson's chart adds citywide data that helps put that small number of injury crashes in context.

This is all the more remarkable when you consider that people have been making between 30,000 and 40,000 bike-share trips every day, so the bike-share zone almost certainly accounts for a significantly greater share of overall NYC bike trips now than it did before Citi Bike. With the share of bicycling increasing inside the bike-share zone and the share of bike injuries holding steady, Citi Bike is, if anything, making it safer to ride a bike. More evidence of safety in numbers.

Swanson's charts do show that overall NYC bike injuries have gone up slightly in 2013. But that's true outside of the Citi Bike zone as well as inside. It could be random fluctuation or there might be real underlying causes, but it's not due to bike-share.