Evaluation of the Speed Camera Program in Victoria 1990-1993 Phase 5 : Further Investigation of Localised Effects on Casualty Crash Frequency

Phase 5 of the evaluation of the speed camera program in Victoria builds on the localised effects of the program studied in Phase 3, which found casualty crash reductions in areas within lkm of a speed camera site during high alcohol hours for up to 2 weeks after issue of a speed camera Traffic Infringement Notice (TIN). Phase 5 had 2 main aims; (1) To investigate the localised effects of the speed camera program on casualty crashes in rural towns and on rural highways in Victoria and (2) to calibrate the localised speed camera effects on casualty crashes in Metropolitan Melbourne established in Phase 3 of the evaluation. The Phase 5 analysis covered speed camera operations and casualty crashes occurring in the period July 1990 to December 1993. Analysis in Victorian rural towns was unable to find a statistically significant localised speed camera effect on casualty crashes within lkm of a camera site when considering either influence due to camera site operations or receipt of a TIN. When considering casualty crashes within a 15km radius of a speed camera site on Victorian rural highways, a statistically significant reduction in crash frequency was observed on arterial roads in high alcohol hours in the week following the presence of a speed camera, whilst a weakly statistically significant crash reduction was observed in low alcohol hours on all roads in the 2 weeks following the issue of a speed camera TIN. However, these results should be treated with some caution because of firstly the weak statistical significance and secondly, the inability to find a corresponding effect when a 5km radius of influence was considered. Analysis of localised speed camera effects in metropolitan Melbourne considered the effects on casualty crashes occurring within a lkm radius of a speed camera site. A statistically significant reduction in crash frequency was found in high alcohol hours on all roads for up to three weeks after the issue of a speed camera TIN, with the effect apparently diminishing across this period. A statistically significant crash reduction for 1 week after camera operations at a site was also found on arterial roads in both high and low alcohol hours. These results were much more reliable, statistically, than those reported for rural highways.