Road safety evaluation and target setting using data envelopment analysis

Abstract

At present, comparisons between countries in terms of their road safety performance are widely conducted in order to better understand one's own safety situation and to learn from other countries. In this respect, crash data such as the number of road fatalities and casualties are mostly investigated. However, the absolute numbers are not directly comparable between countries. Therefore, the concept of risk, which is defined as the ratio of road safety outcomes and some measure of exposure (e.g. the population size, the number of vehicles, or kilometres travelled), is often used in the context of benchmarking. Nevertheless, these risk factors are not consistent in most cases. In other words, countries may have different evaluation results or ranking positions using different exposure information. In this study, data envelopment analysis (DEA) as a performance measurement technique is adopted to provide an overall perspective on a country's road safety situation, and further assess whether the road safety outcomes registered in a country correspond to the numbers that can be expected based on the level of exposure. More specifically, 2007 data for 26 European Union (EU) countries (except Malta) in terms of the number of inhabitants, passenger cars and passenger-kilometres travelled are used as the model's inputs and the number of road fatalities as the output. As a result, an overall road safety efficiency score is evaluated. Furthermore, based on the model results, best-performing and underperforming countries are identified, and specific benchmarks are indicated for each underperforming country. Moreover, challenging targets are given for each underperforming country by learning from its benchmarks, enabling policymakers to recognize the gap with other countries and further develop its own road safety policy.