Resolving some methodological issues in Road Safety Evaluations: The Victorian TAC campaigns revisited

Since their implementation, the TAC campaigns have been extensively evaluated and the mixed results obtained by different researchers have generated much public debate. The true effects of most countermeasures are unknown and may never be known. In estimating their impacts on road safety, analysts have to make a variety of assumptions regarding the relationships between variables and depending on their beliefs, the outcomes may differ considerably. The purpose of this paper is to review conceptually some of the differing assumptions adopted by the different researchers and empirically testing several of these assumptions and model specifications using the same data from previous studies (Cameron et al, 1993; Newstead et al, 1995; White et al, 2000), with the aim to improve our conceptual and methodological understanding of road safety evaluation