Investment models analyse the costs and benefits of road construction and improvement. Accidents are a financial and social cost to countries; minimising accidents through road improvements can provide significant benefits. The Highway Development and Management (HDM-4) model is a commonly used economic tool for ensuring that roadworks are undertaken optimally. Currently HDM-4 has a safety module which predicts accident rates using national road class data. However, the module operates upon only road class and traffic and is time-consuming to calibrate. Thus this module is infrequently used. Relationships between accident rates and factors such as curvature and lane width have been established in several developed countries. However, there are few relationships from developing countries where rates are high and the poor are particularly vulnerable. With road and transport authorities and universities in India and Tanzania, TRL has collected accident, traffic, pedestrian, inventory and condition data and derived HDM-4 relationships which enable accident rates to be more realistically predicted from readily available information and simple calibration. These improved relationships allow more accurate socio-economic, cost-benefit and whole life cost analysis of road construction and improvement. They can also determine if safety improvements such as footpaths or wider shoulders are justified and should be adopted into national policies and standards. (a) For the covering entry of this conference, please see ITRD abstract no. 0612AR242E.
Abstract