The project that are going to be presented deals with ways of controlling traffic flows by use of climatological data collected at road side weather stations. In a large number of countries a Road Weather Information System (RWIS) have been installed in order to give information to maintenance personals about road winter parameters. In Sweden this system has been in use for more than 15 years. The system consist of more than 600 field stations sided in areas where large variations in temperature and early risk of road icing can be detected.
In order to develop the weather information system and also to use the gathered climatological data in a more sophisticated way a project has been initiated which aims at developing different kind of models for automatic control of speed limit in relation to winter road conditions.
Important parts in the weather model are:
* definitions of hazardous weather conditions
* climatological data needed in order to give wanings for these
conditions
* spatial variations of local and micro climate conditions
A test area in the south-eastern part of Sweden has been selected. A highway with a high frequence of winter road accidents have been equipped with variable message signs which are connected to the field stations sited along the same road stretch. Traffic flow and speed adjustment are measured in order to evaluate the obeyence of the road users.