Study on Factors that Determine the Effectiveness of Toll Discounts

In Japan, the low ratio of use of expressways causes various social problems including congestion on general roads running parallel with the expressways, worsening of the roadside environment and traffic safety. One reason why expressway usage is so low is that most expressways in Japan charge tolls, which drivers tend to feel are too expensive. Diverse and flexible toll measures are being implemented to make Japan’s expressways more user friendly and encourage drivers to use them more often. This study analyzed the effects of such toll measures on expressway of traffic volume. The analysis revealed that (1) for the country as a whole, it is the index of traffic congestion on general roads running parallel with expressways that affects the volume of traffic on expressways; (2) in the case of commuter and business traffic, it is the existence of large cities that affects the volume of traffic on expressways; and (3) in the case of through traffic, it is the time when drivers enter expressways and the ratio of large vehicles on general roads running parallel with expressways that affect the volume of traffic on expressways. In the future, we intend to apply the results of this study to make additional proposals for more diverse and flexible toll measures.