A risk model for analysis of road traffic has been developed for the Norwegian Public Roads Aministration. The model applies to the barrier concept in the area of road safety, examplified by head-on and single accidents. The concept barrier presently achieves considerable attention in risk management, for instance in the nuclear and offshore oil and gas industry. The term is used in slightly different ways, but usually a rather wide definition is applied. The standard ISO 17776 notes that barriers may be physical (shields, materials, protective devices, segregation etc.) or non-physical (procedures, training, drills, inspection etc.). The paper presents a suggested list of relevant safety barriers as a basis for the accident analysis. Each barrier has a specific function either to prevent accidents or reduce consequences. Observe that when a precautionary measure is refered to as a barrier it is implicitly assumed that it is followed up in a systematic way. The risk model also includes risk influencing factors (RIF). The RIF represents factors/conditions that affect the probability to a) initiate deviations, b) achieve recovery to normal driving situation or c) reduce the consequences of accidents. A RIF can affect road, vehicle or driver. In total 55 road traffic accidents are investigated and the paper demonstrates that the mdel provides a good tool to analyze and extract rather complete information from the accident analyses. Further, it gives a common format, which makes it possible to aggregate the information from a number of accidents in a rather systematic way. Thus, the analyses of a number of accidents will give a basis for the evaluation of barriers and RIF in the road traffic. This will give valuable data for prioritising amongst risk reduction measures, both technical, human and organisational (A). For the covering abstract of the conference see ITRD E212343.
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