Phase 3 tests for a reduction in casualty crash frequency and severity where speed cameras were used in Melbourne from 1 July 1990 to 31 December 1991. The effect is inferred from comparing crashes which happended on days when the speed camera influence was assumed to be present with crashes which happended on days when the speed camera influence was assumed to be absent. A statistically significant reduction was found in casualty crashes within 1 km of a speed camera as a result of the receipt of a Traffic Infringement Notice (TIN). This appreared to have affected drivers in the vicinity of the site for two weeks after receiving the penalty. The effects appears to have been confined to `high alcohol hours' of the week on arterial roads. There was no statistically significant reduction in the crashes which occurred during the week immediately after speed camera use. There was no evidende of a difference in crash severity following the speed camera influence. Phase 4 concluded that the percentage of vehicles exceeding the speed limit by more than 15 km/h decreased from November 1989 to March 1990 and remained at a lower level in both 60 km/h and 75 km/h speed zones. No significant change in the mean speed was detected. The distribution of vehicle speeds recorded in 100 km/h speed zones did not change.
Abstract