In order to guarantee a maximum safety to road users in wintertime, salt spreading is organised as a precaution. The METEOROUTES programme was set up to optimise salt reaction. This programme allows to determine the spread rate and to plan spreading just before the occurrence of danger. In comparison with the former situation when spreading was decided according to general meteorological forecasts and the experience of the co-ordinators, METEOROUTES has had to prove its usefulness. This new technology is based on : (1) 50 automatic weather stations located alongside the road and motorway network; (2) a communication network allowing links between the weather forecasters, the PEREX centre (permanent station for network operation) and the road network managers; (3) a forecasting programme for determining road surface temperature up to 16 hours ahead; and (4) a programme generating instantaneous and forecasting thermal maps. As METEOROUTES is the main decision tool concerning winter serviceability, it had to be integrated into the general organisation. The validity of the results and the reliability of whole the communication system had also to be ensured. The hereafter mentioned main lines of action have been followed : (1) a continuous data exchange between road managers and PEREX (Traffic Control and Information Centre.); (2) constant scientific follow-up by a professor of climatology of Liege University; (3) the control of round the clock forecasts by the Air Force METEO WING; (4) a rigorous maintenance contract managed by the Electromechanics Directorate; (5) the use of high performance hardware and software; and (6) training courses in software use. All these management approaches fit in with a well-defined scheme enabling the decision-makers to refer to a tool which is as reliable as possible. A group of specialists form a follow-up committee and join their efforts with a view to ensuring the continuity of all the system developments. METEOROUTES thus constitutes an essential component of the Walloon policy as regards the improvement of the service to the users, in the same way as the traffic management carried out within the framework of the W.H.I.S.T. programme (Walloon Highway Information System for Traffic).