Intelligent Transport Systems is being employed to alleviate traffic congestion, environmental loads and other traffic woes in parallel with various other improvement measures. National Institute for Land and Infrastructure Management, Ministry of Land Infrastructure and Transport (NILIM) is devoted to the development of a traffic simulator, referred to as Smart Infrastructure Performance Analyzer (SIPA), which comprehensively evaluates the effectiveness of traffic congestion countermeasures to be taken. This paper discusses the latest effort by the NILIM to achieve an enhancement of SIPA, which has been upgraded by adding functions of a model for merging. A series of tests conducted to evaluate the replicability of the simulator as well as its outcome are reported. Major congestions on expressways have been ascribed to vehicles merging onto expressways, which is particularly true on Metropolitan Expressways in Japan. The conditions which lead to entangled situations on merging and perpetuate congestion at merging sections need to be explicitly identified, and the potential of ITS together with other traffic regulation measures (to reduce congestion and lane change) is analyzed in the process. A traffic simulator to precisely replicate traffic merging is a critically indispensable tool for assessing the effectiveness of ITS and other measures to be employed before actually implementation.
Abstract