Throughout the CRCOG region, the CTDOT Green Light program is evaluating and optimizing traffic signal timings. The resulting benefits are measured by before and after travel time runs. Travel time runs are when a vehicle is driven though the study limits at the peak traffic periods of a typical workday. The vehicle’s speed, stops, delay, and travel times are recorded for both directions of travel. A sample CTDOT Green Light video below displays side-by-side comparison of before and after travel time runs on Route 218 (Cottage Grove Road/Putnam Highway) demonstrating the typical time savings observed.

A benefit-to-cost analysis was completed for each phase study area to understand the return benefit based on the State’s investment. The average annual benefit of all four Phases is estimated at $1,900,000 per year over a 4-year period. The Consultant’s cost of all four Phase evaluations is $100,000 per year for 4 years. The average annual benefit-to-cost ratio for all four Phases is calculated to be 19:1.

This shows a significant return on investment to Connecticut motorists through a reduction in delay and fuel consumption. Additionally, the reduction of stops and emissions provide a benefit to the air quality in Connecticut. Less stops at traffic signals may also provide added safety benefits through reducing crashes.

Average Annual Benefit-to-Cost Ratio

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