Identification of spatial hotspots for road safety improvement: Case of Northern Ireland

In recent years, the concept of composite performance index, brought from economic and business statistics, has become increasingly used in the field of road safety. The construction of the composite safety performance index (CSPI) involves the following key steps: the selection of the most appropriate indicators to be aggregated and the method used to aggregate them. Over the last decade, various aggregation methods for estimating the CSPI have been suggested in the literature. However, recent studies indicates that most of these methods suffer from many deficiencies at both the theoretical and operational level; these include the correlation and compensability between indicators, as well as their high “degree of freedom” which enables one to readily manipulate them to produce desired outcomes [7], [8], [9]. In this study, we introduce an alternative non-linear aggregation method for the estimation of the CSPI, which is then used to identify and rank temporal and spatial hotspots for Northern Ireland. The obtained results highlight the stability and consistency of the proposed method, through a successful reduction in the deficiencies associated with traditional aggregation methods. Furthermore, the developed method can be viewed as an intelligent support system for road safety evaluation.