Vision Zero Tool Box

There are a variety of interventions that we use in the City of Cambridge to increase the safety of people who walk, bike, take transit and drive in the City. 

Rectangular Rapid Flash Beacons (RRFBs)

What are they?

RRFBs: Rectangular Rapid Flash Beacons are solar powered pedestrian activated flashing warning lights for unsignalized midblock crosswalks. RRFBs are an improvement on older-style flashing warning lights because they have a faster flash frequency (about 190 times per minute), a brighter light intensity, a strobe feature to better capture driver attention, and they only flash when a pedestrian is present.

Why install?

The traffic department conducted yield studies on numerous unsignalized midblock crosswalks comparing those with and without pedestrian activated warning lights and the data shows a substantive increase in the yield rate of drivers approaching crossings equipped with these types of warning devices. Studies done nationally corroborate with our results.

Recently through the City’s Participatory Budgeting process residents have voted for $176,000 in funding for more RRFBs to be installed at 10 locations throughout the city.


Mass Ave / Davenport St

Mass Ave / Washburn Ave

Prospect St / St Paul St

Huron Ave / VFW (#680)

Alewife T Station Access Rd

Portland St / Albany St

Oxford St / (#19)

Under Construction:

Mass Ave / Dudley St

Prospect St / St. Mary Rd