The City of Richmond installed a 4.7 million dollar advanced signal system at 262 signalized intersections and evaluated its impact on the central business district (CBD). The system was designed to coordination signal timing on four routes having independent signal timing plans. Timing was optimized using a system event schedule and the TRANSYT-7F signal timing optimization program. The timing plans were implemented using a central computer system and subsequently fine tuned based on input from drivers who compared traffic flow, signal phasing, splits, and offsets to platoon progression diagrams for each route. Field data were collected during peak periods using a test vehicle equipped with an automatic data collection system to record travel times, delays, stops, emissions, and fuel consumption before and after system deployment.
A series of runs performed on representative test sections on each route indicated that travel times decreased 9 to 14 percent, total delays decreased 14 to 30 percent, and stops decreased 28 to 39 percent.
An annual savings of 326,020 vehicle-hours of delay, 495,530 vehicle-hours of total travel time, approximately 76 million stops, and nearly 2.9 million liters of fuel resulted in an annual cost savings of about $4.2 million.