Here's a map from the Globe of bike accidents reported to Cambridge police from 2010-2014 [0]. Unfortunately the map no longer loads for me, but the accidents are mostly along major roads and the area is still discernible, especially when compared side by side with a map of the area [1]. As the article says, Cambridge Street, Broadway, Beacon Street, and Mass Ave are all hot spots.

Would love to see data combined with Somerville, since I'm sure the stretch of Beacon between Porter and Inman would be similarly populated. These are also only accidents reported to police, so I would bet they lean towards more serious accidents.

[0]: https://www.bostonglobe.com/metro/2016/10/05/map-bike-crashe... [1]: https://www.google.com/maps/@42.3773046,-71.1224085,14z