San Francisco's streets can be dangerous for bicyclists. Several high profile deaths, including that of Amelie Le Moullac in August, have drawn attention to the safety of people using bikes to get around town.
A new data visualization from the You Are Here group at MIT—the folks behind the independent coffee shop map—backs up the anecdotal sense of where the problems are with an exact count of where most of our crashes occur.
The most dangerous intersections include Market and Valencia, Harrison and 13th, and Fell and Divisadero. Those aren't completely surprising—after all, they are along the standard transportation corridors in the city.
What's more interesting is how some of the other crash hotspots are in new and unexpected places. Like the two at Polk and Pine and Polk and Turk. Or the huge clustered centered roughly on Oak and Divisadero. In some ways, you can trace where the up-and-coming neighborhoods are—and aren't—by the number of bike crashes. By that metric, places like the Inner Sunset, the Geary Corridor, or the Dogpatch still have a long way to go.
Also, in many ways, the bike crash map overlaps with the clusters of no-fault evictions and tech bus stops found by the Anti-Eviction Mapping Project. Which isn't to say that the Google Bus is causing bike crashes. Instead, it's just a reminder that, sure enough, most things happen where most people are.
In general, the highest amount of crashes occurred along Market Street, Mission Street, and Haight Street. As you leave the downtown core, the street seem to get safer for cyclists—relatively few crashes occur in the Sunset, the Richmond, or in the south parts of the city.
There's a few caveats to keep in mind with this map: It measures 307 bicycle crashes that took place from 2012 to 2013 drawn from data kept by the Police Department. That means that crashes that weren't reported to the SFPD aren't included in the data set. More importantly, because it displays the absolute number of crashes, it doesn't tell you what the relative levels of danger are. You'd need information on the frequency of bicycle trips for each intersection to plot that.
Nevertheless, the map is a fascinating visualization of the all-too-common amount of bicycle accidents.