Risk factors examined in more detail: 50 km/h intersections : a closer look at the concept of Safety Performance Indicators (SPI’s) in fatal crashes and quantification of red light running. Safety Performance Indicators (SPI’s) are achievement indicators for road safety related to risk factors in traffic that can be used by policymakers for proactive road safety policy. Policy makers show increased interest in road safety assessment instruments for proactive policy making that can be used in a 'risk based' approach. That essentially means that on the basis of scientific insights governments take measures beforehand at locations and in situations that show road safety hazards. This report takes a closer look at the concept of SPIs. The following research questions needed to be answered: 1. What definitions of performance indicators in general and of SPIs in particular are found in the literature and how can SPI’s understood from a conceptual frameworks ? 2. Which SPIs are distinguished in the literature and which of these are possibly relevant for the road safety context in the Netherlands ? 3. Can other possible SPIs be identified ? 4. What is the state of affairs concerning the substantiation of the SPIs under points 2 and 3 and with the relationships between them ? 5. What problems do researchers experience with the conceptual framework of SPIs, and what problems do policymakers experience with the concept of SPIs ? 6. How can research contribute to solutions for the problems identified ? 7. Which SPIs are relevant to further investigate and underpin and why ? 8. Which of these factors do we actually find back in serious crashes on roads in the Netherlands ? 9. What is the quantitative relationship2 between one or more of these factors and the occurrence of crashes and casualties, and which methods are suitable for such quantification ?
Abstract