New Detection Technology

Most traffic signals have detection equipment to track when traffic arrives at the intersection to provide or extend a green light. Detection of arriving vehicles can be achieved in a variety of methods including inductive loops, radar, and video equipment.

The traditional detection practice in the State of Connecticut was using inductive loops. Inductive loops require a “coil” of wire installed in the pavement. When a vehicle enters the magnetic field of the loop, it places a “call” into the signal computer indicating a vehicle is present. Potholes, pavement damage and even seasonal temperature changes can break loop wires. When a coil of wire develops a break, the computer detects that a vehicle is always present even when there are no vehicles. This results in additional delay until the detector is repaired. At first, the break can go unnoticed, and the signal operates at reduced efficiency until the CTDOT can detect and coordinate the repair.

Improving Detection

The CTDOT is in the process of transitioning to more advanced technology for detecting vehicles, relying on video and radar detection equipment. Centrally networked, these systems provide notification when the equipment requires repair. Repairs can be completed independent of pavement reconstruction schedules and can be accomplished during winter months. Occasionally, inductive loops will be placed where the new technology cannot achieve reliable detection.