VicRoads is developing a dynamic Variable Speed Limit System on the Western Ring Road in Melbourne, Australia. The aim of the variable speed limit system is to improve road safety and traffic flow on the Western Ring Road. The Western Ring Road is a major urban freeway in the western part of Melbourne that carries approximately 100,000 vehicles per day and large proportions of heavy vehicle traffic. The road consists of a divided carriageway and is 26 km in length. The speed limit on the road is 100kmh. High traffic volumes on the Western Ring Road at certain times of day can cause breakdowns in flow, which results in traffic congestion and accidents. The proposed variable speed limit system will predict traffic congestion using traffic information being collected from the road and determine the most appropriate safe driving speed to optimize traffic flow. Variable speed limits will be conveyed to motorists by a series of roadside electronic variable speed limit signs. Changes to the variable speed limit signs will occur automatically based on traffic conditions but will also be capable of being manually operated from VicRoads Traffic Control Center during times of emergency. All changes to the speed limits on Western Ring Road shall be logged and transmitted to the VicRoads Traffic Control Center in real time as well as to a fixed digital speed camera system that will also operate on the road. This paper provides an overview of the proposed operation of the Variable Speed Limit System and examines the: (1) aims of the system; (2) proposed system operation; (3) key components of the system; and (4) status of the system's implementation. Dynamic, real time variable freeway speed limits have the potential to provide significant benefits in terms of efficient traffic flow and road safety improvements.
Samenvatting