Signal Spotlight: Greenwich Arch Street Corridor Adaptive Signal Project

In late April, the Town of Greenwich Department of Public Works unveiled the long-awaited Arch Street Corridor Improvement project, which was funded through the Congestion Mitigation and Air Quality (CMAQ) program. Arch Street is a minor arterial in the town and connects I-95 to Route 1 and to downtown Greenwich, which includes a railroad station, retail and commercial businesses, large office facilities, the town’s Teen Center, Greenwich Harbor, recreational facilities, a hotel and numerous restaurants. The roadway has an Average Annual Daily Traffic (AADT) of approximately 35,000 vehicles and serves numerous pedestrians.

The improvement project’s highlight was the installation of Adaptive Signal Control Technology (ASCT), the first ASCT project in Connecticut. The project strategically installed cutting-edge Miovision cameras on traffic signals to collect and analyze traffic data on directional traffic flow, vehicle delay, and lane queue length. These cameras can detect the type of vehicle (car, SUV, truck, tractor-trailer) traveling through the intersection as well as pedestrians and bicyclists. Intelligent software receives the current traffic information provided by the cameras and automatically optimizes the traffic signal timing. Each traffic control box communicates with the others in real-time through a fiberoptic network loop. Additionally, the pedestrian signals were converted from exclusive to concurrent to further optimize signal operations.

“Adaptive Signal Control Technology (ASCT) makes traffic signals more effective and efficient. Unlike traditionally timed traffic signals, ASCT accommodates changing traffic patterns and calculates a traffic signal timing plan based on the changing traffic conditions on the roadway caused by traffic crashes, special events, road construction, and other roadway incidents in realtime,” said Gabriella M. Circosta Cohee, P.E., Town of Greenwich Senior Civil Engineer and Project Manager. “The new adaptive traffic signal system can detect an influx of vehicles and can improve the traffic congestion by instantly adjusting the timing of the traffic lights at all five intersections.” This was a key component of the project to minimize congestion and reduce peak-hour queues onto I-95, address heavy volumes during incidents on I-95 and optimize progression through the closely spaced intersections on Arch Street.

Also installed as part of this project, another first in Connecticut, is a flashing yellow left-turn arrow at one of the intersections. According to the Deputy Commissioner of Public Works Jim Michel, “We are excited to be a leader for the state of Connecticut in implementing new and advanced infrastructure that can decrease vehicle emissions and improve air quality. This project is an example of how the Department of Public Works can make a positive impact for our residents today and for future generations to come.”

Like many projects in the past two years, the Arch Street project was impacted by the pandemic. When asked about the challenge of overseeing such an important project in the center of town during this time, Ms. Circosta-Cohee had this to say, “Having been handed a one-of-a-kind project was challenging enough, but then the bids for this project were due on the same day that Town Hall went into COVID lockdown.  During the past 2 years we changed the way we do things to keep the ball rolling.  I learned so much throughout this project and I am extremely grateful to have worked with such knowledgeable people at Urban Engineers and the NY-Conn Corporation.”

Well done Gabriella and the rest of the Greenwich Public Works team!

Resource:
Town of Greenwich, Department of Public Works Press Release, April 26, 2022