Metrication of the urban speed limit and pedestrian fatalities

In the early 1960s the urban area speed limit was increased from 30 to 35 mph in Victoria and NSW. With the introduction of metrication in 1974 the urban area speed limit of 35 mph (56 km/h) was changed to 60 km/h throughout Australia. The reason why 60 km/h was selected is discussed. A study of the likely relationship between travelling speeds and the incidence of pedestrian fatalities was conducted by the NHMRC Road Accident Research Unit (now the Centre for Automotive Safety Research) based on the results of detailed investigations of 176 fatal pedestrian crashes in the Adelaide area between 1983 and 1991. A reduction in the urban area speed limit from 60 to 50 km/h was predicted to result in a reduction of 30 percent in the incidence of pedestrian fatalities. The method developed to estimate this reduction is described and compared with the method used in more recent case control studies of travelling speed and the risk of casualty crash involvement. The effect on pedestrian fatalities where the urban area speed limit has been reduced from 60 to 50 km/h is also noted. Based on the above information, the consequences of the choice of 60 rather than 50 km/h for the urban area speed limit are estimated in terms of the incidence of pedestrian fatalities in Australia since 1974.