Research Papers

Motor Vehicle Collision Trends in Ontario’s Young and Novice Drivers: A Retrospective Cohort Study from 2001-2006

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Date added May 8, 2011
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Category 2011 CMRSC XXI Halifax
Tags Session 5A
Author/Auteur Christopher Meaney, Mary Chipman

Abstract

Purpose: The aim of this analysis is to estimate and compare both crude rates and adjusted relative risks of motor vehicle collision in young and novice drivers in Ontario. We will investigate whether differences in the magnitude of the crude rates or adjusted risks can be accounted for by factors, such as: license class, gender, age, and suspension or conviction history.

Methods: A retrospective cohort design was employed. Driver records for those with G1 (beginner), G2 (intermediate) or G (full) licenses in Ontario, aged 16-24 on January 1, 2001 were selected from an Ontario Ministry of Transportation (MTO) database. The cohort was followed from January 1, 2001 to December 31, 2006. The number of police-reported collisions incurred during this interval by individuals in each license class was enumerated. Rates of collisions (per 100,000 driver-days licensed) were calculated by license class at time of event, gender, age at study start date, and suspension/conviction history. Negative binomial regression was used to assess the adjusted impact of license class, gender, age and suspension or conviction history on the risk of collisions. All summary statistics and regression models were estimated following a reclassification of the outcome variable to document whether the police officer reporting the collision classified the driver as “driving properly” versus “not driving properly”.

Results: At the study start date, cases included 3,621 beginner drivers (1%), 133,515 intermediate drivers (48%) and 142,245 full class drivers (51%). Slightly more males (54%) were observed than females (46%). At the beginning of the study, 8% of cases were 16-17 years of age, 52% of cases were 18-20 years of age and 40% of cases were 21-24 years of age. The total number of collisions incurred over the six years of observation was 164,242. The overall rate of collisions was 26.84 per 100,000 days licensed (95% CI: 26.64-27.04). The rate of collisions in beginner, intermediate and full license class drivers was 3.72, 36.64 and 26.28, respectively. Males had higher rates of collisions than females. Younger persons also had higher rates of collision. Those with a history of either suspension or conviction had higher rates of collision than drivers who had never had their motor vehicle license suspended or been convicted of a traffic violation. Adjusted relative risks from the multivariate negative binomial models were in concordance with the trends observed in the crude rates.

Conclusions: Graduated driver licensing (GDL) programs are designed to prepare individuals to adequately handle the risks of driving. Beginner drivers were observed to have a markedly lower rate of collisions compared to intermediate drivers. The lower rates of collisions observed in beginner drivers are likely a result of the GDL restrictions placed on this license class. When many of these restrictions are removed, the rates of collisions increase in intermediate drivers and surpass rates for fully licensed drivers. This finding suggests that enhanced exposure, practice and training is required for beginner license class drivers or that a different subset of restrictions may need to be considered for intermediate license class drivers.

Christopher Meaney, Mary Chipman