Applicability of AHS Service for Traffic Congestion in Sag Sections

Sag sections and tunnels cause 35% of the congestion on expressways in Japan. One of the factors in congestion is imbalance in traffic lane utilization such as traffic concentration in the passing lane and leeway in the cruising lane. Therefore the National Institute for Land and Infrastructure Management (NILIM) and the Advanced Cruise-Assist Highway System Research Association (AHSRA) have been studying AHS services that would optimize the traffic lane utilization rates by providing drivers with information before congestion occurs. This paper will report on our analysis of actual traffic conditions at a congestion location in a sag section (in the Tomei Tokyo-Nagoya) Expressway). It will also report on the results from examination of the possibility of providing service, the algorithms for determining the timing for service.