RESPONSIBILITY ANALYSIS - A METHODOLOGY TO STUDY THE EFFECTS OF DRUGSIN DRIVING

In order to study the role of drugs in driving, a responsibility analy sis was developed to allow an assessment to be made of the driver's cu lpability or responsibility in an accident. Factors possibly mitigatin g drivers' responsibility in each accident were identified and scored. Factors considered were: condition of road, condition of vehicle, dri ving conditions, accident type, witness observations, road law obedien ce, difficulty of task, and level of fatigue. If a sufficient number o f mitigating factors were identified a driver would be found to be eit her partly or totally exonerated from blameworthiness and scored eithe r as a contributory or nonculpable driver. If drugs present in a drive r contributed to accident causation, it would be expected that they wo uld be overrepresented in culpable drivers, i.e. those drivers not exo nerated from blame. A total of 341 driver fatalities occurring in Vict oria were analysed for blood alcohol content (BAC). Twenty-nine percen t had a BAC over .05% (the legal limit in Victoria). Alcohol-positive drivers were statistically overrepresented in the culpable group (p < .001), in single-vehicle accidents (p < .05) and those accidents in wh ich vehicles left the road for no apparent reason (p < .001). Odds-rat io estimation of relative risk of culpable and nonculpable drivers sho wed that the relative risk rose disproportionately to BAC.