Bicycle Crash Information

Bicycle Crash Summary Report

The City of Cambridge has been analyzing bicycle crash data in depth and a summary fact sheet is available here. Crash data since January 2010 is publicly available from the Cambridge Police Department through the City of Cambridge Open Data Portal.

What Does the Crash Data Tell Us?

The good news: the bicycle crash rate has been decreasing in Cambridge over the period of time we have been tracking data to enable us to determine a crash rate. Information on the crash rate and how it is calculated can be found in the Bicycle Crash Summary Report, and more recent information about bicycle crash reporting and data can be found in Chapter 3 of the 2020 Cambridge Bike Plan.

Crash Rate Trend

The less good news: every crash is one too many and we need to work assiduously to continue to reduce the crash rate.

What Are the Most Prevalent Kinds of Crashes?

The most common bicycle-motor vehicle crashes in Cambridge are: motorists entering a main street from a side street hitting a cyclist; motorists opening a car door in front of a bicyclist; and motorists turning left in front of a straight-moving cyclist. Other crashes types of concern include motorists sideswiping bicyclists, often when parking or leaving parking spaces, and motorists turning right in front of a straight moving cyclist and motorists.

Crash Type Graph

What Can Be Done to Address Crashes?

Outreach and education to remind motorists that they are sharing the streets with more vulnerable road users is essential. Most crashes are the result of driver inattention and we all need to be aware of who is on the road with us.

Watch for Bikes - Driver Education

The City of Cambridge continues to work to remind motorists of their responsibilities in the “Watch for Bikes” campaigns.

Highlights of the "Watch for Bikes" Brochure:

  • LOOK before turning
  • LOOK before opening a car door
  • LOOK before you enter a main street out of a driveway or side street 

Bicyclist Education

Bicyclists should always be aware of their surroundings and other road users while traveling in the city. Particular things to watch out for are car doors (always travel 3’ away) and turning vehicles at all intersections and driveways. Cyclists should also make sure to have lights at night – this is so that people can see *you*! And remember that cyclists must also yield to pedestrians at crosswalks and shared paths. The City has free bicycle classes for Cambridge residents and employees throughout the year for those who would like some extra tips or trainings.

 Image of happy cyclist

Roadway Design

Well-designed roadways enhance safety for all users. By providing facilities for bicyclists on our city streets, a message is given to cyclists that they are welcome and to motorists to expect and watch for bicyclists.

While most well-designed bicycle facilities have safety benefits, recent data indicates that protected bike lanes and cycle tracks show the greatest safety benefits. While these are not feasible on every street, they are being looked at on more major streets such as the ones currently in existence or planned in Cambridge (Vassar Street, Concord Avenue, Western Avenue, Binney Street, Ames Street). See here for a detailed report about cycle tracks.

In addition, Cambridge has had a substantial traffic calming program for over a decade, to reconstruct roads and intersections in such a way as to reduce traffic speeds and make the environment more conducive for bicycling and walking. The projects have been successful in reducing speeds, which is safer and more comfortable for all users.

Safety in Numbers

Cities with higher numbers of cyclists are safer not only for cyclists but for all users. This has been called the “safety in numbers” effect. Some of the reasons for this:

  • The more cyclists there are, the more motorists will see them and know to look out for them
  • Cities that are comfortable for cycling are those where bicycle infrastructure is better and speeds are lower, a safety benefit for all
  • When more people bike, those are likely the same people who are also sometimes driving and may be more likely to think of cyclists
  • More cycling is usually correlated with less driving

Youth bicycling

For More information

Here are a few references if you are interested in reading more about data and research: 

Staff Contact

For more information on the Bicycle Program, contact Cara Seiderman:, 617/349-4629.