A Dynamic Signal Control Approach for Integrated Ramp and Mainline Metering

Freeway merges are one of the most significant sources of traffic congestion. This study proposes a dynamic signal control algorithm for an integrated ramp and mainline metering control strategy to improve freeway operation and reduce environmental impacts at freeway merging areas. The presented algorithm uses real-time traffic sensor information to predict the future status of downstream queue and dynamically control the signal. For safety reasons, the mainline signal control is activated only when a significant speed drop is detected at all lanes of the mainline and the traffic has been already almost stopped. The results of the simulation analyses on a real-world calibrated network show a maximum of 15.7% improvement in average speed, 20.9% reduction in average delay, and 13.7% decrease in CO emission.