Preliminary review of reductions in fatal and serious casualty crashes in Victoria during late 1996 and early 1997

Monash University Accident Research Centre - Report #135 - 1998

Authors: K. Diamantopoulou, S. Narayan & M. Shtifelman

Abstract:

An on-going system of data gathering and analysis to monitor and evaluate countermeasures was established during 1995. The data collected by the system, including number of random breath tests, number of speed related traffic infringement notices, television publicity levels associated with various themes (i.e. drink-driving, speed, concentration, fatigue, seat belts), unemployment rates, weather data, alcohol sales and fuel sales, was used to review the apparent reduction in fatal and serious casualty crashes that occurred in Victoria during late 1996 and early 1997.

A reduction in fatal crashes occurred in Victoria during September 1996 to June 1997, with the reduction being primarily in rural areas. Country Victoria experienced larger reductions in fatal crashes than Melbourne during the December 1996, March 1997 and June 1997 quarters relative to the average of the corresponding quarters of the previous five years. In parallel, a reduction in serious casualty crashes occurred in Victoria, commencing about September 1996, but was relatively smaller than the fatal crash reduction. For rural areas the serious casualty crash reduction may have begun earlier - about June 1996 - but for Melbourne a decrease was not evident until November 1996.

A reduction in the number of vehicle kilometres travelled in Victoria was found for July 1996-June 1997. This may have contributed to the crash reduction. However, when the number of fatal crashes and the number of serious casualty crashes were adjusted by the amount of travel in Victoria, there was still evidence of reductions during late 1996 and early 1997 for rural areas and for Victoria as a whole, but less so for Melbourne. This suggests that some factor other than a reduction in exposure (i.e. vehicle travel) is contributing to the fatal and serious casualty crash reductions.

In addition to the decreased vehicle travel and decreased crash rates, a substantial reduction in rainfall was found for both Melbourne and country Victoria during September 1996-June 1997 when compared to the same period a year earlier. There was also a small increase in average daily sunshine hours during September 1996-March 1997, with the increase being greater in rural areas than in Melbourne. These changes may also have contributed to the crash reductions.

In view of the exploratory nature of this preliminary study, further research involving statistical modelling as well as the collection and analysis of a further six months crash and explanatory data the for the period July-December 1997) is needed to determine the contribution and significance of the above factors in the reduction in crashes that occurred during late 1996 and early 1997.

Executive Summary

An on-going system of data gathering and analysis to monitor and evaluate countermeasures was established during 1995. The data collected by the system, including number of random breath tests, number of speed-related traffic infringement notices, television publicity levels associated with various themes (i.e. drink-driving, speed, concentration, fatigue, seat belts), unemployment rates, weather data, alcohol sales and fuel sales, was used to review the apparent reduction in fatal and serious casualty crashes that occurred in Victoria during late 1996 and early 1997.

In parallel, a reduction in serious casualty crashes occurred in Victoria, commencing about September 1996, but was relatively smaller than the fatal crash reduction. For rural areas the reduction may have begun earlier - about June 1996 - but for Melbourne a decrease was not evident until November 1996. In addition, for rural areas, the percentage reductions in serious casualty crashes were larger than the corresponding fatal crash reductions during the December 1996, March 1997 and June 1997 quarters. For Melbourne, however, small increases occurred during the March 1997 and June 1997 quarters relative to the average of the corresponding quarters of the previous five years.

A reduction in the number of vehicle kilometres travelled in Victoria was found for July 1996June 1997. This may have contributed to the crash reduction. However, when the number of fatal crashes and the number of serious casualty crashes were adjusted by the amount of travel in Victoria, there was still evidence of reductions during late 1996 and early 1997 for rural areas and for Victoria as a whole, but less so for Melbourne. This suggests that some factor other than a reduction in exposure (i.e. vehicle travel) is contributing to the fatal and serious casualty crash reductions.

Sponsoring Organisation: Baseline Research Program - Department of Justice, Transport Accident Commission, Royal Automobile Club of Victoria (RACV) Ltd, VicRoads