Balancing Efficiency and Equity of Ramp Meters

Abstract

A new freeway ramp control objective - minimizing total weighted travel time is presented in this study. This new objective function is capable of balancing efficiency and equity of ramp meters, while the previous metering objective - minimizing total absolute travel time is purely efficiency-oriented and hence produces a most efficient but least equitable solution. When certain assumptions hold, this metering objective is shown to be equal to minimizing non-linearly weighted ramp delay. A simulation method to achieve the new metering objective is developed and demonstrated using the example of BEEX, a new ramp control strategy also developed in this study, in a microscopic traffic simulator.