Analysis of the Effectiveness of Freeway Ramp-Metering with Computer Simulation

The purpose of this study is to analyse the effectiveness of freeway ramp metering with PARAMICS, which is a microscopic traffic simulation program. Since 1970s, various ramp metering algorithms have been developed and some of them are already applied in the fields. However, most of the studies dealing with the effectiveness of ramp metering focus mainly on the improvement of mainline traffic and it is not well known whether ramp metering improves the total traffic system including ramp and adjacent highway. This study analyses the system-wide effectiveness of four ramp metering algorithms, ALINEA, Bottleneck, Zone, and SWARM. The results show ramp metering reduces total vehicle travel time up to 7% and coordinated algorithms such as SWARM and Bottleneck do not outperform over ALINEA or Zone algorithms. It is also shown that there exists a non-linear relation between the effectiveness of ramp metering and the parameters.