Operational efficiency of signalized intersections in Al-Khobar, Saudi Arabia

Abstract EN

Almost all signalized intersections in Saudi Arabia are operated with total directional separation, i.e., by allowing a separate phase for each direction.

Furthermore, the signal splits are adjusted on a trial-and-error basis without any calculations.

This causes many operational and environmental problems and driver frustration.

This study aims, first, to investigate the extent of the problem and, second, to analyze alternative phasing and signal characteristics for the purpose of operational improvements.

Two signalized intersections on crossings of a major arterial by a major arterial and two on a major arterial by a collector street were selected for the purposes of this study.

Existing signalization and various signal alternatives were analyzed using a signal optimization and simulation package (SOAP).

Finally, capacity analyses were performed to establish and compare the levels of service of the existing signalization and the best signal phasing scheme which was selected by SOAP.

Study showed that considerable improvements in stopped delays, excess fuel consumption, excess left-turning vehicles, and levels of service could be achieved through signal optimization.

In the study area alone, SR 8 million/year for vehicle operating costs and SR 50 million/year of time savings could be realized simply by signal optimization.