Variable Speed Limit (VSL) systems are a type of Intelligent Transportation System (ITS) that utilise speed detection, weather information, and road surface condition technology to determine safe speeds at which drivers should be travelling given current roadway conditions. These advisory speeds are usually less than the posted speed limits, and can be displayed on overhead or roadside variable message signs (VMS). A study has recently been initiated, by the Federal Highway Administration, to identify and characterise the usage of VSL throughout the world. This paper provides preliminary findings of this study. The paper focuses on the role that speeding plays in rural crash causality and describes foreign and domestic applications of VSL systems. General conclusions and descriptions of future work to be performed under the project are also presented.
Samenvatting