Citation

Al-Kaisy A, Freedman Z. Transp. Res. Rec. 2006; 1978: 49-60.

Affiliation

Department of Civil Engineering, Montana State University, 213 Cobleigh Hall, Bozeman, MT 59717

Copyright

(Copyright © 2006, Transportation Research Board, National Research Council, National Academy of Sciences USA, Publisher SAGE Publishing)

DOI

unavailable

PMID

unavailable

Abstract

This paper presents a systematic investigation into the effects of adverse weather on signal operation and the potential benefits of implementing weather-responsive signal control. The investigation considered isolated and coordinated signalized intersections in urban and suburban areas under various traffic conditions. Both operational and safety analyses were conducted in this investigation. Traffic signal optimization and microscopic traffic simulation were used to perform the operational analysis with average travel time as a performance measure. The safety analysis used the adequacy of change and clearance intervals and the presence of dilemma zones as indicators of safety at signalized intersections. Study results suggest that operational benefits of weather-responsive signal control are generally significant and that the greatest benefits can be realized at coordinated corridors in town and city centers. Results also suggest that dilemma zones are most likely introduced on a particular intersection approach once the coefficient of friction between tire and pavement drops below the design value of a wet pavement. Further, a set of recommended guidelines that relate weather conditions to operational impacts and potential benefits of weather-responsive signal timing was developed and provided in this study.