The Manager's report back on the possibility of posting truck exclusion on Roberts Road

Subject: Awaiting Report 21-40 – Request for Truck Exclusion on Roberts Road

This memorandum has been prepared in response to Order 8 from the May 17, 2021 City Council Meeting (Awaiting Report 21-40) requesting that the Traffic, Parking, and Transportation Department (TP+T) explore the possibility of posting a truck exclusion on Roberts Road. Roberts Road is a one-way residential street, traveling from Kirkland Street near the Somerville/Cambridge border to Cambridge Street. There is one southbound travel lane with residential parking on both sides.

The road is subject to a posted Safety Zone speed limit of 20 MPH as well as an overnight truck exclusion, which was approved in 2013. Land use along the street is primarily residential, but the street does also provide access to the rear parking lots and loading areas for the Harvard

Vanguard Medical Associates Building at 1611 Cambridge Street and the retail plaza

at 1613 Cambridge Street.

Truck Exclusion Procedures

Heavy commercial vehicle exclusions on all public rights-of-way are subject to approval by the Massachusetts Department of Transportation (MassDOT). The procedures for obtaining an exclusion are laid out on page 11 of the Massachusetts Amendments to the 2009 Manual on Uniform Traffic Control Devices (January 2012).

Roberts Road Analysis

To determine if expanding the truck exclusion on Roberts Road to cover all hours of the day would be appropriate, on September 14th and 15th of this year, TP+T conducted 48-hour traffic counts (which is a typical data collection period to understand traffic volumes and truck percentages). The counts include traffic volumes, speeds, and classifications of vehicles broken down on an hourly and a daily basis. The counts indicate that an average of 983 vehicles per day travel down Roberts Road. Speeds were low, with an 85th percentile speed of 23 mph and an average speed of 18 mph. The counts indicated that 2.9 percent of the vehicles traveling down Roberts Road were classified as heavy vehicles, or approximately 33 per day. Given the low volume of heavy vehicles on Roberts Road, it is not expected that a truck exclusion would be approved by MassDOT if we submitted an application. The Page 2 of 2

Massachusetts Amendments to the 2009 Manual on Uniform Traffic Control Devices

(referenced above) states that truck exclusions are typically only approved on roads where the truck volumes make up between 5% and 8% of the vehicle volume, as compared to less than 3% on Roberts Road. Furthermore, an exclusion does not apply to vehicles with a destination within the local area around the street. Given the loading access to buildings on Cambridge Street, it is likely that a significant percentage of these vehicles traveling on Roberts Road do have a local destination and thus would not be subject to an exclusion. Based on this data and analysis, TP+T does not intend to move forward with a request to MassDOT for a full-time truck exclusion for Roberts Road.