Abstract

A methodology was developed to find appropriate travel times for highway links using data from point detectors that could be at various points within the link or could even be outside the link. The travel times were found using a definition that the appropriate value is the one experienced by a virtual vehicle reaching the midpoint of the link at the midpoint of the time step. A simple iterative scheme was proposed to find the travel time profiles. The accuracy of the scheme depends on whether aggregated detector data or individual vehicle spot speeds are used. Comparison of estimated travel times with actual experienced travel times of all vehicles in a microscopic simulation showed the technique to give very good results, comparable with having a high number of probe vehicles reporting travel times.