TIME DEPENDENT CORRELATIONS BETWEEN TRAVEL TIME AND TRAFFIC VOLUME ON EXPRESSWAYS

Abstract

This study analyzes time-dependent correlations between travel time and traffic volume in urban expressways. Traffic volume can be changed by many factors and is necessary to know what factors are important. Congestion can be one of the most important factors. It is natural to consider that drivers avoid congested roads and this can make negative correlations between travel time and traffic volume in neighbour hour. In addition, congestion may influence traffic volume in remote hours. It is important to check such “time-dependent” correlations to examine policies like dynamic congestion pricing and so on. This study analyzes the time-dependent correlation between travel time and traffic volume with data obtained with traffic detectors. As a result, negative correlations are observed in neighbour hours and positive correlations are observed between daytime travel time and night traffic volume. This indicates that congestion can have relationship to traffic volume in later hours.