Quality of probe vehicle data on travel time estimation

Abstract

The purposes of this study were to investigate accuracy and reliability of travel time information and to assess the effectiveness of probe vehicle in providing traffic information (travel time) under various traffic conditions. A widely used traffic microsimulation model, Paramics V5, was used to generate travel time data on a hypothetical network that was vuilt according to geometrics of corridor, traffic flow parameters and configuration of signalized intersection. Average travel time on links and routes were analyzed for various percentage of probe vehicles (market penetration) and traffic flow conditions (level of congestion) and compared to the ‘true’ average travel time. Moreover, the variation of travel time data obtained from probe vehicles was examined from ‘bootstrapping’ technique where this method of resampling represents the varying condition for probe vehicles. It was found that the plots of probe vehicle average travel time versus ‘tree’ average travel time for link and route case agreed well which imply the obtainment of travel time accuracy by probe vehicles in wide range of traffic volumes (situations). However, the probe vehicle performed less accurately when traffic congestion was forming. A case study of network and traffic condition similar to a real world condition was carried out to demonstrate the quality of travel time data from probe vehicles in selected routes (OD). It was clear that when having all vehicles in the link to be probes, the OD estimates are rather rlilable.