Factors affecting the severity of motor vehicle traffic crashes involving young drivers in Ontario.

OBJECTIVES To assess the factors affecting the severity of motor vehicles traffic crashes involving young drivers in Ontario. POPULATION Ontario young drivers, aged 16 to 20, involved in traffic crashes resulting in injury, between 1 January 1988 and 31 December 1993, on public roads in Ontario. METHODS Population based case-control study. Cases were fatal injury, major injury, and minor injury crashes involving young drivers. Controls were minimal injury crashes involving young drivers. Cases and controls were obtained retrospectively from the Canadian Traffic Accident Information Databank. Unconditional logistic regression was used for data analysis. RESULTS Factors significantly increasing the risk of fatal injury crashes include: drinking and driving (odds ratio (OR) 2.3), impairment by alcohol (OR 4.8), exceeding speed limits (OR 2.8), not using seat belts (OR 4.7), full ejection from vehicle (OR 21.3), intersection without traffic control (OR 2.2), bridge or tunnel (OR 4.1), road with speed limit 70-90 km/hour (OR 5.6) or 100 km/hour (OR 5.4), bad weather (OR 1.6), head-on collision (OR 80.0), and overtaking (OR 1.9). Results of the same model applied to major and minor injury crashes demonstrated consistent but weaker associations with decreasing levels of crash severity. CONCLUSIONS A casual relationship between crash severity and the risk factors listed above was proposed. Risk factors recommended for preventive intervention include: alcohol consumption, speeding, and use of seat belts. Head-on collisions are of primary concern.