In 2009, Commonwealth Avenue in Boston had the second highest bicyclist crash rate in the city of Boston. As part of continued efforts by the city to create continuous, safe bicycle facilities leading west of the city and to connect cyclists to a number of dedicated off-road paths, in 2010, the city of Boston installed a left-side bike lane on Commonwealth Avenue between Kenmore and Arlington Streets.
A left-side bike lane was selected over a right-side lane for several reasons. Commonwealth Avenue has problems with double parking which would have undermined the effectiveness of a right side bike lane. The left side lane decreases the risks of “dooring” and takes advantage of an underpass that averts a busy intersection at Massachusetts Ave. Conditions for the intersection at Arlington favored the construction of a left-side lane. The lane also runs alongside the historic Commonwealth Avenue Mall, which is a positive environment for cyclists and discourages cycling inside the park.
The facility required several modifications to the roadway. The number of vehicle lanes was reduced from three to two in both the underpass, and from Kenmore St. to Charlesgate West. A buffer was created between the roadway and the bicycle lane leading into and out of the underpass. The project included the creation of five bike boxes at access points to the Charles River Pass, as well as a designated waiting area for cyclists who failed to shift from the right to the left side lane.
Project Proposal Slideshow
Commonwealth Avenue Plans