QUALITY IMPROVEMENT OF WINTER SERVICE IN DENMARK

During Denmark's winter season, the usual number of days with snow is from 5 to 10, with a total snowfall of 30 to 50 cm. A typical winter day will see a temperature of around 0 deg C, with thawing in the daytime and a slight frost at night. This temperature pattern often creates a risk for a white frost on the roads in the early hours together with freezing wet road surfaces. Thus on the main roads there is a yearly average of 95 salting actions, with a variation from season to season from 60 to 140 actions. In Denmark the roads are administered by three authorities: the state, counties, and municipalities. Among the municipalities the standard for winter services varies a lot; however, on the state and county roads service is provided throughout the country according to the following principles: 1) The decision of a call out is taken at county winter centrals. The decision includes both county and state roads. There are 13 winter centrals manned all hours to handle this task. 2) Private contractors carry out the salting and snow clearing, and they normally provide the drivers and equipment. The spreaders and snowplows are owned by the road authorities. 3) The service objective always is to have "black road surfaces" (i.e., either dry surfaces or wet surfaces). Thus, preventive salting actions are carried out on the basis of prognoses for slippery roads. In carrying out their task, the winter centrals have two essential tools, the road weather information system (RWIS) and Vinterman. The operator at winter central uses the countrywide RWIS to survey the development in the weather and the road conditions. The tool is essential in connection with call outs for salting and snow clearing. When the decision is made, Vinterman is used for starting, surveying, managing, and following up on the call out. At the same time, the system issues information to the traffic information center and the media so that road users can be updated on the situation. In the development of the Danish RWIS and Vinterman systems great emphasis has been placed on enabling the systems to ensure the best possible quality in both decision and implementation of a call out.