MEASURES TO ENSURE TRAFFIC SAFETY FOR TWO-LANE MOTORWAYS (EXPRESSWAYS) WITH SMALLER TRAFFIC VOLUME (EFFORT IN JAPAN)

摘要

Japan's expressway network is roughly 80% complete, and the remaining sections are notexpected to see heavy traffic; thus for the foreseeable future, operational planning assumestwo-lane, two-way traffic. Tragic head-on collisions have occurred on Japan's two-laneexpressways as a result of vehicles straying into oncoming traffic.With Japan's declining birthrate and a growing proportion of elderly people, no significantincrease in traffic demand is expected for the majority of Japan's traffic routes and sections.Thus, for those roads which expansion to four lanes was not anticipated in initial planningand those expressways which have been maintained as two-lane expressways since theirestablishment, the speed of certain services and the level of road safety can be effectivelyincreased by installing a safety barrier between the opposing lanes of traffic in order tophysically separate them. For some routes and sections, this road structure has beenimplemented and is in operation.Thus, this report will look at a) the background study, b) the challenges involved in full-scaleimplementation and c) the measures taken to overcome those challenges for theimplementation of this road structure.