Benefits of Proactive Monitoring of Traffic Signal Timing Performance Measures - Case Study of a Rapidly Developing Network

Abstract

Some insight into the benefits of regularly and frequently maintaining traffic signal timings within and across jurisdictional boundaries is provided. The rapidly growing Cranberry Township located at the crossroad of two interstate highways (Pennsylvania Turnpike (I-76) and I-79) in the state of Pennsylvania, twenty miles north of Pittsburgh is used as a case study. Environmental and economic costs due to the absence of monitoring and updating traffic signal timings are estimated. While traffic signal timing optimization and coordination is a cost effective strategy to reduce travel time and its consequential air emissions along corridors, implementing such timing plans are only effective at and around the time of implementation, while travel demand remains constant. As times passes, with the fluctuation of vehicular demands, especially in rapidly developing areas, timing plans need to be monitored and modified. In Cranberry Township such developments and travel demand fluctuations result in significant increase in costs of travel (time and fuel) and external environmental costs. Estimates show that timing plans that were at their optimal level at the time of implementation, in less than two years result in 18 percent increase in the cost of fuel, 13 percent increase in the cost of travel time and 11 percent increase in the external environmental costs, if left unmodified.