A Probe-Based Variable Speed Limit System

Abstract

This article presents the results of an evaluation of a candidate variable speed limit (VSL) system that takes the space mean speeds (SMSs) from probe vehicles as its main input. The presented algorithm extends the capability of a model predictive control (MPC) VSL model with the input of SMS derived from vehicle probes and their corresponding space-based densities, instead of spot-based densities and detector speeds. The developed probe-based VSL was evaluated on an 8-km stretch of Highway 2, in Calgary, Alberta, Canada, using Paramics microsimulation software. The performance of the probe-based VSL algorithm was examined under various traffic conditions and probe vehicle parameters. The findings of the probe-based VSL analysis support previous findings taking input from point detectors and showing that the efficiency of the VSL strategies was efficient only for a limited range of traffic conditions. The results of the analysis show the effectiveness of developing advanced freeway control algorithms that...