Traffic safety has traditionally been measured in terms of accident frequencies and severities and/or a measure of accident exposure. Absolute frequencies (e.g. accident numbers) alone provide insufficient information to adequately assess the safety of a particular location or to evaluate the performance of an accident countermeasure. Details of the operation of a countermeasure and the accident process are required to provide better understanding of accident causation and to develop more effective countermeasures. `Improved safety' is a primary goal of much Local Area Traffic Management (LATM) work, but the evaluation of accident countermeasures in local areas, based on accident statistics alone, is difficult as these accidents tend to be spread area-wide in low quantities. Although the concentration of accidents in local areas is low, a significant safety problem exists - up to one-third of all urban casualty accidents occur on local streets. Pedestrians and cyclists, especially the old and the young, are particularly vulnerable. Traditional evaluation techniques have limitations when applied to local area studies, especially when statistically conclusive results are sought. This paper describes the rigorous evaluation of the safety benefits resulting from two `case studies' of LATM schemes in metropolitan Sydney, in the municipalities of Canterbury and Willoughby. In each of these cases before and after periods of a minimum of three years' duration each were available. This was set as a minimum criterion for analysis, and the two LATM schemes evaluated were the only ones available that met this criterion (A).
Abstract