Abstract
The highway traffic congestion is one of the most important social and technical issues from the early days of motorization in Japan. Accordingly, the highway capacity has long been a major concern of traffic engineers, not only in research but also in practice, in order to alleviate the traffic congestions. Also, the concept of the quality of service of traffic flow and its proper understanding according to diverse conditions are crucial for implementing the performance-oriented highway planning and design schemes. This article therefore overviews the recent research works regarding highway capacity and quality of service particularly in Japan, after reviewing the state of the arts in bottleneck phenomena observed on Japan motorways and highways. And the future perspective of these research fields is discussed.
