Arch Street Corridor Traffic Improvements

Arch Street Corridor

Congestion Mitigation and Air Quality (CMAQ)

Town Project No. 12-34


As part of a Congestion Mitigation and Air Quality (CMAQ) grant application, the Town of Greenwich identified the Arch Street Corridor as an area that could benefit from the implementation of Adaptive Signal Control Technology (ASCT). Arch Street has an Average Daily Traffic (ADT) Volume of approximately 35,000 vehicles per day.  An adaptive traffic signal system modifies traffic signal timing parameters in real-time and in response to changes in traffic flows. The primary purpose of providing ASCT in the Arch Street corridor is to detect and respond to heavy traffic volumes in the project area in a timely and efficient manner to improve the safety and movement of people and goods through the corridor. Specifically, ASCT will maximize the efficient use of green time at intersections, minimize queuing onto the I-95 mainline during heavy commuter peaks, heavy volume days, and incidents on I-95, and optimize progression through the closely spaced intersections along Arch Street.


As part of the project, exclusive pedestrian phasing will be converted to concurrent pedestrian phasing. The existing pedestrian signal at the Teen Center has been converted to a Rectangular Rapid Flashing Beacon (RRFB) and moved slightly east of an existing pedestrian crossing.


This project focuses on five signalized intersections including one pedestrian crosswalk in the Town of Greenwich, Connecticut.  The project area and physical changes include:

  • Arch Street & Railroad Avenue
  • Arch Street & Horseneck Lane
  • Arch Street & I-95 Southbound Ramps
  • Arch Street & I-95 Northbound Ramps
  • Arch Street & Teen Center (Currently Pedestrian Only Signal) - The existing pedestrian signal was removed and replaced with a rectangular rapid flashing beacon (RRFB) at the existing crosswalk slightly east of the existing pedestrian signal.
  • Arch Street & Steamboat Road/Museum Drive - The Southbound Steamboat Road approach was modified to include an exclusive right turn lane due to the high volumes making this turning movement.

Arch Street north of I-95 provides access from the freeway to the Greenwich Metro-North railroad station, several large office facilities, the downtown Greenwich shopping district, and U.S. Route 1 (Putnam Avenue).  Arch St. south of I-95 provides access from the freeway to the Teen Center, Greenwich Harbor, office facilities, hotels, and restaurants.  


As part of this project, all mast arms, traffic signals, detection equipment, cabinets, and handholes were replaced.  The system was upgraded from twisted-pair copper to fiber optic. The signalized intersections in this project have been connected via fiber optical cable to the central system.

DPW applied for and received a grant for the design and construction of the project, which is 100% reimbursable under the Federal Highway Administration’s Congestion Mitigation and Air Quality program. The total participating grant amount allocated to the Town for this project is $2,333,180.

Public Information Meeting No. 1 – May 16, 2016:

The Town of Greenwich, DPW Engineering Division along with the Town’s consultants, held a Public Information meeting to introduce the project to the public. The Town presented the project background, explained how adaptive signal systems work, proposed impacts, and next steps.  The Town obtained input from the public and proceeded with the final design.



Arch Street Corridor Press Release  October 29, 2021 

Public Information Meeting No. 1 – May 16, 2016, Meeting Summary and Slides


Contact:               Gabriella M. Circosta Cohee, P.E., Senior Civil Engineer, DPW Engineering Division


Phone:                  203-861-3151