by dougsears on Tue Feb 09, 2010 2:04 pm
Memorandum
To: Steve Sadwick, Community Development Director
From: Beverly Woods, Executive Director
Subject: South Street Traffic Analysis
Date: February 5, 2010
Based on data provided by AECOM, MassDOT’s consultant for the Lowell Junction project, the NMCOG
transportation staff has analyzed existing traffic conditions at key intersections along South Street in Tewksbury, in order to ascertain whether the roadway currently operates at an acceptable level of service and to quantify the impact of additional traffic on the operations of the roadway. The analysis examined the operating conditions under the scenarios outlined in AECOM’s Memorandum, dated November 18, 2009, which was provided to the Task Force. The AECOM memo examined the following buildout scenarios for the Priority Development Sites within the Lowell Junction area, and assumed that access to future development would be provided via South Street:
Scenario 1 - Development under by-right zoning in all three Lowell Junction communities, without a new interchange
Scenario 1A - 40B development is assumed for the Tewksbury PDS, and by-right development for the Andover and Wilmington PDS parcels, without a new interchange
Scenario 2 - Regional retail development for the Tewksbury PDS using the HCOD overlay district, and by-right development for the Andover and Wilmington PDS parcels, with a new interchange
Scenario 3 – Mixed-Use development in Tewksbury and Wilmington, and by-right development in Andover, with a new interchange
Scenario 3A - Light industrial/R&D development in the Tewksbury PDS and by-right development in Andover and Wilmington, with a new interchange.
Geometric Conditions
South Street is generally 22 feet wide, which exceeds the minimum design requirement for a roadway with a local functional classification. There are several large trees lining the roadway, making expansion difficult. Any widening or expansion project would require the removal of many mature trees, and would impact the character of the neighborhood.
South Street and Bridge Street Intersection
There are sight distance issues for vehicles turning from the southbound approach of South Street due to the curvature of the existing roadway. The intersection itself is very large and there is a need for better delineation and traffic channelization as part of any mitigation project.
Existing conditions analysis shows that the intersection operates well with a level of service (LOS) A during the peak travel periods of the day. Under Scenarios 1 and 1A, the South Street southbound left turning movements will deteriorate to a LOS F during both AM and PM peak hours without any mitigation being provided. Saturday peak operating conditions will remain acceptable under both of these scenarios. Scenarios 2, 3, and 3A do not add enough additional traffic to South Street to inhibit the operations at this intersection. Under all three scenarios, the intersection will operate at LOS B or better for each movement.
Hill Street at South Street Intersection
Under each development scenario, the intersection of Hill Street and South Street will continue to operate at an acceptable level of service during the A.M. Peak period and the Saturday Peak period. However, during the P.M. Peak, the eastbound turning movements experience unacceptable delays, operating at level of service E under Scenario 1A. Operations during the P.M. peak remain acceptable under the other scenarios analyzed.
Salem Road at South Street Intersection
Under existing conditions, traffic operations analysis of the intersection of Salem Road and South Street shows that the northbound and southbound movements experience unacceptable delays during both the A.M. (LOS E) and P.M. (LOS F) peak travel periods. Adding additional traffic under the various development scenarios only exacerbates the already unacceptable delays for the South Street movements. During the Saturday peak hour, Scenarios 1 and 1A experience unacceptable delays for southbound South Street movements. All other scenarios operate under acceptable conditions.
Conclusion
As shown in the attached table, development of the Lowell Junction area without the new interchange would overwhelm the local street network (assuming access to the development area was provided via South Street), with unacceptable operating conditions occurring at the intersections of South Street and Bridge Street, South Street and Hill Street, and South Street and Salem Street. The South Street and Salem Road intersection already experiences operational deficiencies, and any additional traffic will only cause further deterioration of operating conditions. At this point in time, the traffic modeling being conducted by MassDOT’s consultant has not advanced to the stage where NMCOG staff is able to analyze the traffic impacts under the various interchange design alternatives. It is expected that this information will be provided by MassDOT as work on the environmental permitting documents advances.