This document contains two reports which describe the development of improved models for predicting the effect of proposals for investment in road infrastructure on the numbers, severity and costs of road crashes in Australia. The two reports cover rural roads and urban roads separately, reflecting the significant differences between rural and urban conditions in the influence of road infrastructure on road crash incidence, severity and cost. The reports draw on the results of recent relevant studies in Australia and overseas, and explore available Australian data on road crashes. The main focus of the reports is on forecasts of differences in numbers of crashes. In the improved models described in this document, savings are estimated using predicted crash numbers and average crash costs based on average crash severity proportions. The improved models are intended to further improve harmonisation in the economic evaluation of proposals for general road projects. The models are not intended for use in evaluating specific road safety programs or blackspot programs where the emphasis is mainly on casualty numbers and crash types respectively. Inputs for the improved rural model include data on road inventory (road type, surface type, width, horizontal alignment, and overtaking lanes), traffic mix (proportion of cars, rigid trucks, and articulated trucks), crash costs, and crash mix (fatal, injury, and property damage). Inputs for the improved urban model include road type, intersection type, frontage access control, and crash mix. Improved calibration of the models over time is encouraged, based mainly on road inventory and traffic data and crash statistics. (Author/publisher)
Abstract