Evaluation of CTCLS Series Traffic Signal Load Switches in the Field-Bulb Life Determinations, and Development of a Group Relamping Model;Final rept

摘要

Maintaining traffic signals is a significant expense at ODOT. Bulbs fail and need immediate replacement, which entails the expense of traffic control and may involve hazards such as heavy traffic or inclement weather conditions. Two possible technologies to reduce this problem are improved load switches and group relamping. The improved CTCLS series load switches were developed by Conservation Load Switch (CLS) of Westerville, and they were designed to extend the life of traffic signal bulbs by a factor of two to four. This was achieved by gradually 'soft-starting' the bulb over 45 milliseconds rather than sending full power immediately and by using a microprocessor circuit to regulate voltage fluctuations. The CTCLS series load switches had been tested in laboratories and in very small scale field tests, but a large-scale test was needed to verify the manufacturer's claims of doubling bulb life. Group relamping is the process of replacing all traffic signal bulbs at a fixed interval, rather than simply waiting for them to fail before replacement.