Sunday, June 16, 2024

City staff is examining the reports of crashes on Cambridge streets where separated bike lanes are being planned – Cambridge Street, Main Street and Broadway – to identify safety hazards and devise remediations. I appeal to City Manager Yi-An Huang to examine the crash reports for streets that already have “quick-build” separated bike lanes for the same purpose.

On two streets where separated bike lanes were first installed, the number of crashes has increased.

In August 2017 a Pilot Safety Project was installed on Cambridge Street between Quincy and Antrim streets, and in September 2021, Cycling Safety Ordinance “quick-build” lanes were installed on Massachusetts Avenue between Trowbridge and Inman streets. These two segments, Cambridge Street West and Mid-Massachusetts Avenue, are similar to the three road segments now in planning: They have high traffic volumes, had parking and loading areas on both sides that served nearby residents and businesses and are too narrow to accommodate two protected cycle lanes without removing parking on one side. It is to be expected that the addition of “quick-build” lanes will have similar impacts for safety – positive and negative – on the streets in planning.

Cambridge Police Department reports show that the annual numbers of motor vehicle crashes with vulnerable users on Cambridge Street West and Mid-Massachusetts Avenue are no lower than before the lanes were installed and that there are now more crashes involving pedestrians.

The following table of reported pedestrian and cyclist crashes in the CPD database shows the total numbers of crashes for 2015 and 2016, before any lanes were installed, and for 2022 and 2023, after they were installed on both streets.

There were 27 total crashes in the latest two-year period, compared with 21 crashes in the two years before the first lanes were installed. Most of the increase was for crashes involving pedestrians. Crashes involving cyclists also increased.

It’s time to find out if the quick-build design creates safety hazards as it eliminates others.

Expert review of these crashes by police and engineering staff is needed to identify and remedy safety hazards in the new layout to avoid repeating them in new projects.

I appeal for a “data-driven approach” to safety called for by Cambridge’s Vision Zero policy. Genuine progress toward safer streets and zero serious injury crashes depends on it.,


The writer is the former chair of the Cambridge Board of Traffic and Parking. He is the vice chair and interim chair of Cambridge Streets for All.