Most jurisdictions in North America have some version of graduated driver licensing (GDL). GDL programs attempt to provide a more protective environment for novice drivers, typically by lengthening the learning process and imposing a set of restrictions aimed at reducing their risk of collision. To achieve this, most GDL programs are multi-staged and include a learner’s stage and an intermediate stage before graduation to a full license. A sound body of evidence documenting the effectiveness of GDL programs in reducing collisions, fatalities and injuries among novice drivers is available. However, information about the relative importance of individual components of GDL is lacking. Despite the available literature it is still not known which GDL features contribute most to collision reduction and how exactly this is achieved. Consequently, it is difficult to identify how a GDL program should be best designed or improved. The objectives of this study are to calculate a summary statistic of GDL effectiveness, to identify the most effective components of GDL programs, and to help understand how GDL components achieve their effect by applying a meta-analytic approach. Data from 46 American States, the District of Columbia and 11 Canadian jurisdictions are used and were obtained from the Fatality Analysis Reporting System (FARS) for the U.S. and from Transport Canada’s Traffic Accident Information Database (TRAID) for Canada. The timeframe of this evaluation is 1992 through 2006, inclusive. Relative fatality risks and their and 95% confidence intervals were calculated using fatality counts and population data for target and comparison groups, both in a pre-implementation and post-implementation period in each jurisdiction. The target groups were 16, 17, 18 and 19 year old drivers. The comparison groups were 25-54 year old drivers. The relative fatality risks of all jurisdictions were summarized using the random effects DerSimonian and Laird model. Cumulative meta-analyses and meta-regression using Restricted Maximum Likelihood (REML) and Markov Chain Monte Carlo (MCMC) Gibbs sampling were also conducted. Strong evidence in support of GDL was found. GDL had a positive and significant impact on the relative fatality risk of 16 year old drivers (reduction of 19.1%). However, no such summary effects were found for 17, 18 and 19 year old drivers. Significant effects were found for meta-regression models with 16, 18 and 19 year old drivers. Two variables were significant for 16 year old drivers, namely whether there are restrictions on passengers in the intermediate stage (in jurisdictions with passenger restrictions in the intermediate stage, the relative fatality risk of 16 year old drivers decreases) and whether passenger restrictions are lifted or not in the intermediate stage if passengers are family members (lifting the passenger limit in the intermediate stage if passengers are immediate family members leads to an increase in the relative fatality risk of 16 year old drivers). One variable was significant with 18 year old drivers, more precisely mandatory driver education in the learner stage (the relative fatality risk of 18 year old drivers decreases in jurisdictions where driver education is mandatory in the learner stage). Finally, five variables were significant with 19 year old drivers. These variables are length of night restriction in the learner stage (an increase in length of the night restriction in the learner stage leads to an increase in the relative fatality risk of 19 year old drivers), country (the relative fatality risk of 19 year old Canadian drivers is higher than that of 19 year old drivers in the U.S.), lifting night restrictions in the intermediate stage for work purposes (the relative fatality risk of 19 year old drivers increases in jurisdictions where night restrictions are lifted for work purposes in the intermediate stage), exit test in the intermediate stage (the relative fatality risk of 19 year old drivers decreases in jurisdictions that require an exit test to graduate from the intermediate stage), and mandatory driver education in the intermediate stage (there is an increase in the relative fatality risk of 19 year old drivers in jurisdictions with mandatory driver education in the intermediate stage). These results are described, interpreted and further discussed along with the limitations of this study. In conclusion, despite limitations of the study design, some previously established findings have been confirmed and some interesting and intriguing new findings emerged from these analyses. Recommendations for follow-up research are formulated based on the conclusions of this report. (Author/publisher)
Samenvatting