Assessing Potential for Safety Improvement by Safety Reviews of Existing Roads

Traditional road safety engineering work involves implementing relevant remedial measures at high accident locations. A new approach to road safety management is based on safety reviews of existing roads. Road safety review is aimed at identifying and solving risk factors, by trying to investigate how the road environment is perceived, and ultimately utilized by different road users. This approach overcomes the problems arising from poor quantity and quality of accident data. The paper describes the development of a Potential for Safety Improvement index that looks at factors impacting road safety and takes into account how safety measures can reduce accident frequency and severity. The methodology is based on safety reviews of existing roads. One consequence is that preliminary data are not needed. It allows Potential for Safety Improvement index calculation to be a flexible procedure, adoptable by every road agency. Moreover, safety reviews are spreading in many highways agencies around the world and the PSI index complements the review results in order to rank either the reviewed segments and the safety issues. Different PSI indexes are computed: the overall PSI, the PSI of the selected safety features and the PSI of the safety items, which are the characteristics that contribute to the global effect of the features. The specific indexes allow to point out safety concerns where improvements may be cost effective; the overall index provides a measure of potential for safety improvement of the road segments.