Speed Limits in Cambridge

As a part of our Vision Zero efforts, we reduced the speed limit to 20 mph on most Cambridge Streets.

On posted streets, the speed limit is 20 mph.

Reducing driving speeds from 25 mph to 20 mph helps make Cambridge safer for people of all ages and abilities walking, biking, and driving on our streets. Small differences in travel speeds have a big impact on the outcomes of crashes. The graphic below shows the likelihood of severe or fatal injury for pedestrians struck by drivers traveling at various speeds.

Likelihood of severe or fatal injury for pedestrians struck by drivers traveling at these speeds.¹

Show your support

We all share responsibility for ensuring that Cambridge is a safe place for everyone traveling on our streets. Here are a few ways to show your support:

• Be aware of your speed. Drive at or below 20 mph. You can help save lives. If you crash, you’re less likely to cause serious injury or death.
• Help spread the word. Talk with your family, neighbors, and friends about the speed limit changes.
• Stop by our office to get a 20 mph button, sticker, or magnet.
• Join the Vision Zero Cambridge email list.

Default (statutory) speed limits versus posted speed limits

The State rules for speed limits allow a minimum default (statutory) speed limit of 25 mph in Cambridge, or any other thickly settled area. They also require that signs be posted on each street that does not have the default (statutory) speed limit of 25 mph. This means that reducing the speed limit to 20 mph on most Cambridge streets required the installation of a lot of signs.

This work followed the reduction of the default speed limit from 30 mph to 25 mph in December of 2016. It also built off work done in early 2018 to decrease speed limits to 20 mph in the city’s five squares. These speed limit changes were made possible by the State's 2016 Municipal Modernization Act. Chapter 90, Section 18B of the Massachusetts General Laws allows the Traffic, Parking, and Transportation Department Director to establish 20 mph safety zones in the interest of public safety.

20 mph streets

On smaller, primarily local-access streets the speed limit is 20 mph. Larger, arterial roads will still have a speed limit of 25 mph, unless otherwise posted. When in doubt, go 20 mph. The map below shows street segments that have a 20 mph speed limit and the approximate location of 20 mph safety zone signs. White and yellow signs have been installed.