Speed is an inherent characteristic of mobility and a hazard to safety. Several approaches exist of how to manage speed. In the Netherlands, the emphasis has mainly been on harm minimisation during the last decades, due to the implementation of the Sustainable Safety vision. Speed management remains a core business in this vision, by means of an integral approach of speed management measurements. A request from a number of regional authorities to assist them in developing a decision support system for speed management was the starting point for elaborating SWOV's vision on safe speed and credible speed limits (SaCredSpeed) into an algorithm. This vision andalgorithm are presented in this paper. The SaCredSpeed algorithm uses input data of design, image and traffic characteristics of a particular stretch of road to asses a safe speed and speed limit for that particular situation. This safe speed is related to the real speed (V90; optional), and, depending on the fit, the credibility of the speed limit, the enforcement situation (optional), the network function of the road, the condition of the adjacent roads, and the priorities the decision maker wants to set, SaCredSpeed offers suggestions for adaptations. These can consist of a) speed limit adaptations, b) road design adaptations or c) additional enforcementadaptations. This integral approach to speed management from the view of safety and credibility can be a good addition to other speed or safety instruments that exist. The paper concludes with suggestions for further research and international cooperation.
Abstract