What factors actually affect crash severity and how can road safety programs be better targeted

The aim of this study was to develop a methodology that would better focus scarce road safety resources to fix those areas of the road network that have the greatest number of fatal and serious injury crashes. Cost-benefit analysis (CBA) is used to prioritise black spot projects with the economic benefit of a remedial treatment being the difference between predicted costs of crashes with and without the proposed treatment. This was found to have practical implications for improving the prioritisation of road safety crash reduction programs. Categories of crashes were identified, based on differences in average severity and their relevance to possible treatments. The analysis demonstrates the higher priority of projects that address more severe crashes when crash values are determined using: 1. RUM codes rather than DCA codes to include run-off-road on bend crash type codes that indicate the side of the road which the vehicle went off; 2. three speed limit groups rather than two; 3. darkness as against daylight; 4. the area of the State where the crashes are located; 5. whether the crash happened at an intersection or on a freeway/motorway; 6. different types of safety barrier; 7. size of curve radius. (a) For the covering entry of this conference, please see ITRD abstract no. E217612.