Motor vehicle crashes continue to be the leading cause of death for 15- to 20-year-olds (Hoyert & Jiaquan, 2012). Graduated driver licensing (GDL) programs, which are specialized driver licensing systems for beginner drivers, have been implemented in United States to reduce young teen drivers’ exposure to high-risk driving situations while they gain driving experience. GDL programs include three different stages of licensure: (a) a mandatory minimum learner permit period during which new drivers are only allowed to drive under the supervision of a licensed adult; (b) an intermediate period during which the new drivers are allowed to drive unsupervised, but are subject to licensing restrictions regarding passenger ages and the times during which they may drive; and (c) a final stage of unrestricted licensure allowing driving under all conditions. GDL programs in the U.S. hardly represent a single homogeneous intervention; rather, programs vary characteristics such as age and time criteria, lengths of the learner permit and restricted license stages, required hours of supervised practice, and types and lengths of license restrictions included (IIHS, 2012). While there is a growing body of evidence that supports GDL systems as effective for reducing young driver crashes, little is collectively known about which specific characteristics or provisions of GDL programs, such as minimum learner permit holding periods, and what parameters or calibrations of the provisions are associated with the largest crash reductions. Thus, the objective of this study was to conduct a meta-analysis to systematically synthesize research findings regarding the effectiveness of GDL programs and varied components (e.g., learner entry ages, nighttime driving restrictions) for reducing total, injury, and fatal crashes among drivers aged 15 to 20 years. Fourteen studies were included in the meta-analysis and the findings suggest that GDL laws create a safety benefit for 16-year-old drivers and potentially have a safety benefit for 17- year-old drivers, although to a lesser extent. Given the diversity in the configuration of GDL provisions among the States, the individual contributions of these characteristics to the overall observed effect was also of interest, however, insufficient studies with suitable information available existed to answer this question. Further, a valid study of individual GDL provisions may be prohibited by practical limitations on the level of experimental control one could obtain. For example, the mere existence of a curfew provision does not mean it was truly operationalized unless it can be shown the affected population was aware of it, adhered to it, and the police actually enforced it at a meaningful level. Few studies quantified these important process factors. Although the exact effectiveness of individual GDL provisions could not be determined, the meta-analysis uncovered no indication that any provision was necessarily counterproductive for the GDL target audience of 16- and 17-year olds. Thus, a reasonable strategy for any State considering passage of a GDL law might involve enumerating the full range of provisions applicable to that State, determining which could be reasonably operationalized given available resources and support from key agencies and organizations, and adopting as comprehensive an approach as possible. (Author/publisher)
Samenvatting