A communication transmitted from Louis A. DePasquale, City Manager, relative to Awaiting Report Item Number 18-47, regarding a report on safety improvements at Brookline and Chestnut Streets

CITY OF CAMBRIDGE Traffic, Parking, and Transportation 344 Broadway Cambridge, Massachusetts 02139 www.cambridgema.gov/traffic Joseph E. Barr, Director Phone: [phone removed] Stephanie McAuliffe, Assistant Director for Parking Management Fax: [phone removed] Brooke McKenna, Assistant Director for Street Management MEMORANDUM TO: Louis A. DePasquale, City Manager FROM: Joseph E. Barr, Director DATE: June 20, 2018 RE: Awaiting Report 18-47: Brookline St @ Chestnut St Safety Improvements This memo is in response to Order #1 from the April 30, 2018 City Council Meeting (Awaiting Report 18-47), requesting a review of the need for an additional STOP sign or other traffic calming measures at the intersection of Brookline Street and Chestnut Street. Existing Conditions Figure 1 Brookline Street at Chestnut Street (Figure 1) is a four leg intersection with STOP sign control on the Chestnut Street approaches. The intersection has compact geometry with small corner radii that minimize the speed of turning vehicles. Crosswalks are provided across all legs. Brookline Street is one-way in the northbound direction with on-street parking along the left side and a bike lane along the right side. Chestnut Street is two- way with parking on both sides and a single travel lane.

Page 2 of 2 The Traffic, Parking and Transportation Department (TPT) visited the intersection during the morning and afternoon peak periods earlier this year to review existing operations, observe traffic volumes, and assess any existing infrastructure or safety concerns. Staff noted that the existing signage at the intersection is in good condition. Pedestrian warning signs are posted on Brookline Street reminding drivers to yield to pedestrians in the crosswalk. STOP signs and one-way signs are posted on Brookline Street. All-Way STOP Consideration As part of the field observations, staff collected peak period vehicle volumes traveling through the intersection. The data (which was collected on a normal weekday) indicated that during the morning peak hour, approximately 270 vehicles approached the intersection on Brookline Street while 25 vehicles approached on Chestnut Street. Based on these data, the volumes are well below the thresholds to be considered for installation of all-way STOP control, as detailed below. Following an engineering study, all-way STOP control for an intersection is considered when traffic volumes entering the intersecting streets are roughly equal and the following criteria are met: C. Minimum volumes: 1. The vehicular volume entering the intersection from the major street approaches (total of both approaches) averages at least 300 vehicles per hour for any 8 hours of an average day, and 2. The combined vehicular, pedestrian, and bicycle volume entering the intersection from the minor street approaches (total of both approaches) averages at least 200 units per hour for the same 8 hours, with an average delay to minor-street vehicular traffic of at least 30 seconds per vehicle during the highest hour. Given the very low volumes of vehicles on Chestnut Street, all-way STOP control would not be considered for this intersection. If STOP signs were posted on Brookline Street, drivers would likely disregard the signs since there is rarely a crossing vehicle arriving on Chestnut Street. This situation makes it very unsafe for pedestrians/drivers expecting full stops. Traffic Calming Consideration Chestnut Street is included in the Five Year Sidewalk and Street Reconstruction Plan, with design expected to begin next year. This creates an opportunity to consider the installation of traffic calming measures at the Brookline Street/Chestnut Street intersection, potentially including curb extensions and/or a raised intersection treatment. These features would serve to reduce the speed of through vehicles on Brookline Street and further enhance yielding behavior at the crosswalks, and would need to be considered as part of the overall planning and design process for Chestnut Street.