This blog has reported before on the difficulty of obtaining usable traffic crash data from NYPD. However, there are several alternative sources. These are operated by private citizens who take the raw data from the PDF files released by the New York Police Department and turn them into interactive maps and other formats that allow viewers to quickly see the picture of NYC traffic accidents.
For example, a Pratt Institute professor has developed maps of different aspects of New York’s traffic, publishing them on a blog called I Quant New York. One recent blog post focused on bicycle accidents that were reported to NYPD in 2013.
There were at least 3,800 incidents in which there was at least one injury. The operator of I Quant New York created a heat map to show where the greatest number of bicycle crashes and injuries occurred. He breaks down the data so that it is possible to understand why there are certain “hot spots” for bike accidents.
For example, the map shows that the East Side of Lower Manhattan has more bicycle crashes that than West Side. The blogger speculates that this is the result of bikes coming off the Brooklyn Bridge, with no corresponding source of bike traffic on the West Side.
Maps by themselves just cannot tell the whole story, which must include density of ridership. For example, if a neighborhood has very few bike accidents, does that make it safer? That depends on how many bike riders there are. If there are only a few bicycle riders in a neighborhood and only a few crashes, in theory that neighborhood could be more dangerous than one with many more crashes but also a much higher density of riders. In other words, determining neighborhood safety for bicycle riders requires analysis of more than simple crash data.