The Manager's report back on safety improvements on Walden Street at the intersections of Concord Avenue, Garden Street, and Sherman Street

Existing Conditions

Figure 1 Walden Street is a two-way street that links West Cambridge to North Cambridge. The roadway begins at Vassal Lane opposite Reservoir Street and continues to Massachusetts Avenue north of Porter Square. Traffic counts conducted in November 2017 indicate that the roadway carries approximately 6,900 vehicles per day, with 85th percentile speeds of 26 miles per hour. The segment of the roadway from Vassal Lane to Garden Street was recently reconstructed as part of the West Cambridge Sewer Separation Project.

The roadway provides a single travel lane in each direction with parking on both sides. No bicycle facilities are provided along Walden Street, and it is not identified in the Cambridge Bicycle Plan as a location where bicycle facilities are prioritized.

Page 2 of 2 The Policy Order requested that we review traffic safety improvement opportunities at the following three locations:

Walden Street at Concord Avenue

Walden Street at Garden Street

Walden Street at Sherman Street

The three intersections are very similar in nature. Each is controlled by a traffic signal that provides simple two- phase operation. No vehicle turn phases are provided and pedestrian movements are concurrent with lead pedestrian intervals, consistent with national best practices and Cambridge’s traffic signal policy.

Crash Data

Crash reports were provided by the Cambridge Police Department for each of the three intersections for a three-year period from 2015 through 2017. The data indicate that there were four crashes at the Concord Ave intersection, three crashes at the Garden Street intersection, and five crashes at the Sherman Street intersection. Each of the intersections had fewer than 2 crashes per year on average, which is below average for a typical signalized intersection.

No obvious patterns were observed in the crash data, and detailed crash data is attached to this memo so that readers can review the specific information about each crash. Based on this review, there do not appear to be significant safety issues at these intersections, although we will continue to monitor these locations as part of our ongoing Vision Zero efforts.

Bicycle Facilities

Due to their limited width and relatively high traffic volumes, none of the roadways under consideration as part of this Policy Order are designated for exclusive bike facilities under the Cambridge Bicycle Network Vision. The plan does call for shared lane facilities on Garden Street which were implemented in this area in 2017.

Intersection Improvements

The West Cambridge Sewer Separation Project recently reconstructed the Concord Avenue and Garden Street intersections with Walden Street. Improvements included reconstructed sidewalks, new accessible pedestrian ramps, and new crosswalks. Upon review of intersection operations for pedestrians, TPT staff have extended the lead pedestrian intervals for Walden Street at Garden Street to five seconds to allow pedestrians additional time to enter the intersection. Given the recent upgrades, we do not recommend any further changes at these locations.

The intersection of Garden Street and Sherman Street was not included in the recent construction work, however there is extensive work currently underway on the northwest corner of the intersection related to a private development project. The resulting temporary conditions for sidewalks and crosswalks hinder completing a detailed assessment of existing operations at this time. We recommend revisiting an analysis of this intersection once the sidewalks and crosswalks are restored to their permanent condition upon completion of that private construction project.