Discussion of traffic signal effect on calculating link travel time and field test evaluation

A series of experiments of probe car systems were carried out in Shenyang of China recently. Several kinds of probe car systems were evaluated in the experiments. The signal issue was exposed in the experiments. This paper discusses the traffic signal effect on link travel time calculation and evaluation. How to process the relation between the link travel time and turning delay caused by signal control became a critical issue during the evaluation procedure. It affects the judgment for the accuracy of probe car system. The paper describes two models for dealing with turning delay caused by signal and compares the difference between them. It introduces a solution to reduce signal effect on link travel time calculation and a method to increase the reliability of evaluation for the link travel time.