Estimating Safety Benefits of Road Improvements: Case Based Approach

Abstract

Improvements to road safety have become a high priority for road authorities due to increasing public awareness and concern of the high social and economic costs of collisions. However, satisfying this priority in an environment of limited budgets and growing fiscal constraints is difficult. It is therefore important to ensure that the funding available for road safety improvements is efficiently utilized. In an attempt to maximize the overall road safety benefits, safety professionals usually invoke a process to evaluate the cost effectiveness of road safety projects. Road safety benefits are normally determined using collision reduction factors (CRFs) that are reported in the road safety literature. However, the results from many previous safety studies are unreliable due to the inability to apply the CRFs to all conditions and because many safety studies suffer from problems with the evaluation methodology and accommodating the random nature of collisions. To resolve these problems, safety analysis software known as the information system for estimating crash reductions (ISECR) has been developed. Information system for estimating crash reductions is an intelligent database that uses a case-based reasoning approach to compile the results from previous road safety research. Information system for estimating crash reductions evaluates the applicability of the results by accounting for site-specific characteristics and the study methodology by assigning a quality score. The system determines the expected CRFs and the range and reliability associated with a safety improvement at a specific location. The evolution of ISECR, a description of current and future enhancements, and the applications for this road safety-engineering tool are the subjects of this paper.