The serious traffic crashes of young drivers and their previous traffic offence histories

To explore the relationship between traffic offences, in particular drink driving and speeding, and subsequent involvement in traffic crashes.

The linked traffic offence and crash records of 73% of an original cohort of 61,000 high school students (Grade 10) recruited in 1988 and 1989 were studied to determine the prevalence of prior offences among 1063 drivers involved in a serious (fatal or hospitalisation) crash (“serious crash class”) and 5543 drivers involved in a less serious crash (“minor crash class”), by year of first (index) crash. Offences were categorized as drink driving, speeding, dangerous driving and other. Cumulative mean number of offences per year for male cohort members without a recorded crash were also calculated; this was not done for females due to probable bias resulting from name change at marriage. Relative risks of a subsequent crash and differences in mean numbers of other offences were computed for serious versus minor crashes in both sexes and for serious and minor crashes versus no crashes in males, adjusting for year of index crash. An effort was made to account for possible over-statement of the size of the group with no recorded crashes (“null crash class”).