Road Safety Performance Indicators: Manual. Deliverable D3.8 of the EU FP6 project SafetyNet

Safety performance indicators (SPIs) are measures (indicators), reflecting those operational conditions of the road traffic system, which influence the system’s safety performance. Basic features of SPIs are their ability to measure unsafe operational conditions of the road traffic system and their independence from specific safety interventions. SPIs are aimed to serve as assisting tools in assessing the current safety conditions of a road traffic system, monitoring the progress, measuring impacts of various safety interventions, making comparisons, and for other purposes. Seven problem areas in road safety were selected for the development of SPIs in Europe, they are: alcohol and drug-use; speeds; protective systems; daytime running lights; vehicles (passive safety); roads (infrastructure) and the trauma management system. The theory behind the development of SPIs in each of the seven safety areas was presented by Hakkert et al (2007)1. The data obtained from the cooperating countries and the comparisons of safety performance of 27 countries2, in terms of the estimated SPIs, were presented in two other reports3 – Vis and van Gent (2007a), Vis and van Gent (2007b). This report is called a Manual as it should assist the countries in establishing the necessary systems of data collection for producing national SPIs, in each one of the predefined safety fields, and to make them comparable on a European level. For each safety area, the report defines quantitative SPIs, demonstrates existing practices for their measurements, provides best practice examples (when available), and details the procedures which are necessary to collect and process the required data for the estimation of the SPIs' set on a national level. Recognizing the potential for road safety improvements coming from the use of harmonized SPIs across the EU, enabling benchmarking as a proven tool in road safety policy, the Member States are encouraged to seek ways of applying a uniform methodology for producing national SPIs. The procedures and methods presented in the Manual should be treated as minimum quality requirements for producing national SPIs, in each one of the predefined safety fields. In addition, the report provides a more general theoretical background concerning the sampling issues in estimating SPIs (in general and in the context of specific SPI areas). Regarding setting up an SPI survey, the main questions considered are: sampling procedure to obtain a national sample; sampling size; sampling error; stratified sampling (combination into a single SPI by weighting); representativeness of the results and estimating confidence intervals of the SPI values. These issues are discussed in Chapter 2 and in the Statistical Appendix.