Evaluation of Ramp Metering Control on Urban Expressway in Cairo

Abstract

Uncontrolled on-ramp merging section is considered as a bottleneck at several locations on urban expressways in Greater Cairo Region (GCR). This study aims to evaluate the impacts of applying ramp metering control on the traffic performance at three critical on-ramp sites on the 6th of October corridor using VISSIM. The simulation models were calibrated using the traffic data collected during peak period. Two different control strategies were tested; fixed-time ramp metering and actuated control for both mainline and on-ramp traffic, and compared to “no control” using average speed, average vehicle delay and on-ramp queue length as performance measures. The results indicated that fixed-time ramp metering could improve the overall traffic performance at merging sections by increasing the speed up to 100% and reducing the average vehicle delay up to 50%. However, fixed-time ramp metering control results in on-ramp queue spillback onto adjacent roads at some sites due to insufficient ramp storage length and huge on-ramp volumes. In this case, the actuated control strategy showed significant improvements on traffic performance at both the mainline and on-ramp, in addition to the whole system by increasing the speed by 25%, reducing the average delay by 11%, and reducing the queue length by 35%.