Optical Remote Road Surface State and Temperature Sensors: Survey of Functionality and Usability

In Finland, the weather conditions are the main cause for most of the traffic problems. Finnish Road Administration (FINNRA) has used many ways to improve the safety of winter traffic. Nowadays the weather and road conditions are being recognized with the aid of Road Weather Information System (RWIS), road weather cameras and also with weather radars and satellite pictures. Special road weather forecasts are produced for the winter maintenance operators. In Finland, the road condition monitoring is internationally highly appreciated, but the requirements are so demanding that there are still things that need developing. It has been tried for several decades to find an easy way to determine skid-resistance. During winters 2004-2008 FINNRA has tested new optical remote road surface state and temperature sensors on the main roads of Southern Finland.