RED LIGHT, GREEN LIGHT

In this article, the authors describe how appropriate timing of traffic signals can decrease congestion, improve air quality, reduce fuel consumption, and minimize aggressive driving behavior. The authors first review the history of traffic signals and outline factors that contribute to poorly timed traffic signals, including equipment malfunction, outdated equipment, insufficient staffing of traffic professionals, and out-of-date traffic analysis. The authors then discuss some state-of-the-art solutions, including retiming signals regularly, coordinating or interconnecting closely spaced signals, the use of traffic signal microprocessors that are capable of multiple timing patterns and remote communications, and appropriate levels of traffic engineers. A final section outlines a recently formulated Federal Highway Administration (FHWA) program designed to provide leadership in mainstreaming traffic signal timing and retiming and to promote coordination as a fundamental part of any transportation improvement plan. Sidebars report on signal retiming efforts undertaken in Oakland, Michigan and in Syracuse, New York.