Challenges and opportunities for improving the SAFESIDE procedure for cost-benefit assessment of roadside safety intervention alternatives

Abstract

Single-vehicle crashes involving impacts with roadside obstacles or vehicle rollover are a major source of traffic fatalities and permanent disabilities. Modern road safety (RS) intervention frameworks are based on the belief that permanent disabilities are unacceptable and that human frailty must be considered in road infrastructure design (Vision Zero); leading to roads and roadsides able to accommodate human errors, and forgiving in the event a driver loses control of his/her vehicle (Sustainable Safety). This recently adopted RS paradigm assigns strong responsibilities to road agencies, urging them to take opportunities for RS improvement throughout the whole infrastructure life cycle, instead of pushing safety decisions and responsibilities mainly to road users. This paper refers to the method for assessing the influence of roadside characteristics in RS developed at the Laboratório Nacional de Engenharia Civil, to support decisions concerning the design of new roads and the redesign and maintenance of operating roads. This procedure sets the framework for the application of cost-benefit analysis to the design of roadside features, including the selection and installation of road restraint systems and support structures complying with European standards. Specific software tools were developed, providing a user-friendly interface, and a suitable platform for incorporating new knowledge into the procedure, and for adapting it to developments in construction and maintenance costs. A description of the procedure is made, with an abridged presentation of supporting outcomes, resulting from the analysis of traffic and detailed accident data registered on Portuguese roads and the observation of in-service performance of installed equipment.