Evaluation and Choice Criteria for Automatic Thawing Agent Spraying Systems

For about 25 years already, automatic thawing agent spraying systems have been a helpful contribution to the task of winter maintenance. These systems allow a quick intervention as soon as a risk of icing of the roadway appears by spraying a liquid thawing agent. The main goal of this paper is to supply an evaluation method that can justify the implementation of an automatic thawing agent spraying system, considering all important aspects. The evaluation is carried out in two steps. First, an opportunity examination allows verifying whether a detailed project for a spraying system is justified. Several opportunity criteria are analysed and judged in a qualitative approach, using statistical or project data, for existing or planned roads respectively. These opportunity criteria are treating road safety, operations, road function and situation, as well as the climate. If the detailed project is judged necessary, the choice of equipment alternatives helps finding the ideal configuration for the examined road stretch using a multi-objective analysis. The choice criteria are graded by the projector and weighed by a group of involved specialists, in order to determine the most adapted equipment alternative. The choice criteria are divided into four categories: economy, environment, traffic and operations.