Use and Validation of Risk-Weighted Speed Observation Data for Countermeasure Evaluation
In the absence of suitable crash data, speed observation data can give an indication of the effectiveness of speed-related road safety countermeasures. It is proposed that the use of risk-weighted data is more appropriate. The aim of this investigation was to develop a method for risk-weighting speed observation data in both urban and rural areas for use as an evaluation tool. Speed observation data was weighted by the appropriate risk of a casualty crash. This enabled the magnitude of the reduction in casualty crashes that could have been expected from a change in the on-road speed distribution to be estimated. The outcomes were validated against the results of a crash-based evaluation of a speed-related enforcement package that was implemented in Victoria from December 2000 until July 2002. They were generally consistent with the crash- based evaluation after the degree of representation of the collected speed observation data was taken into account.