Preliminary investigation of the impact of roadside oral fluid testing and increased penalties on illicit drug-driver fatalities in Western Australia

Background:_x000D_
Illicit drugs such as cannabis and methamphetamine are well-known causes of driver impairment and significant risk factors for crashing and personal injury. In Western Australia, recent research showed that 23% of drivers fatally injured during 2000-2012 tested positive for one or more illicit substances. To combat drug driving, a number of initiatives have been implemented in WA in recent years, namely the introduction of Roadside Oral Fluid Testing (ROFT) (2007) and an increase in drug driving penalties (2011). It is of interest to understand the impact of each initiative._x000D_
_x000D_Aims:_x000D_
To undertake a preliminary investigation of the impact of the WA initiatives on drug related driver fatalities during 2007-2012._x000D_
_x000D_Methods:_x000D_
The de-identified linked crash and toxicology records of WA motor vehicle drivers/riders fatally injured during 2000-2012 were retrieved from WA Police. Time series were constructed of the monthly proportion and rate of fatally injured drivers/riders and analysed using Segmented Regression Analysis to investigate changes, either immediate or longer term, that coincided with the two WA initiatives introduced in 2007 and 2011._x000D_
_x000D_Results:_x000D_
Only ROFT was found to be associated with a statistically significant change in drug driver/rider fatalities in WA: an ongoing monthly reduction of 0.0019 fatalities per 100,000 motor vehicle driver licences issued (p-value=0.0115)._x000D_
_x000D_Discussion/Conclusion:_x000D_
Notwithstanding the identified limitations, the findings provide preliminary evidence of the positive impact of ROFT on drug driving fatalities and the limited impact of more severe penalties on drug driving behaviour in the absence of a corresponding and supportive high level of enforcement.