The Iowa Graduated Driver Licensing program: effectiveness in reducing crashes of teenage drivers. Evaluation of California's graduated driver licensing program. Graduated drivers license programs and rural teenage motor vehicle fatalities. Michigan's graduated driver licensing program: evaluation of the first four years. Graduated driver licensing and teen traffic fatalities. Effects of the California graduated driver licensing program. Graduated driver licensing in Michigan: early impact on motor vehicle crashes among 16-year-old drivers. Effect of a graduated licensing system on motor vehicle crashes and associated injuries involving drivers less than 18 years-of-age. Evaluation of Iowa's graduated driver's licensing program.
Graduated Driver Licensing (GDL) programs vary in the United States in terms of implementation and restrictions. The State of Iowa's GDL program is assessed for its effectiveness in reducing crashes among teenage drivers.
                Time series analysis was used to evaluate police documented crashes involving 16-, 17-, and 18-year-old drivers over a 10 year period, with an intervention identified at the point of GDL implementation.
                After controlling for seasonal trends and auto-correlative effects, a significant reduction in the crash rate of and 16- and 17-year-old drivers was observed due to the GDL implementation. However, there were no significant reductions in crash rates for 18-year-old drivers.
                The analyses suggest that the Iowa GDL program is effective in reducing the crash rates of 16- and 17-year-old drivers but the effects do not sustain for 18-year-old drivers.
                The results suggest that the program appears to be working, however further analysis is needed to determine what factors are preventing lasting effects for these teenage drivers. California's graduated driver licensing (GDL) program was implemented to reduce the high crash risk of teenage drivers. The program enhancements made in 1998 were evaluated in this study using methods that rule out the noticeable downward trend in California teen's fatal/injury crash rates as a possible explanation for any observed crash reductions that could otherwise be mistaken for program effects.
                Monthly per capita fatal/injury crash rates for 15-to-17-year-olds and proportional representations of 16-17-year-olds' nighttime and passenger crashes were analyzed using intervention time series analysis.
                After removing trend, seasonality, and transition effects in the data, no overall reductions in fatal/injury crashes for 15-17-year-olds or 16-year-olds (separately) were found to be associated with the 1998 program enhancements, suggesting no overall exposure reduction effect of the longer instruction permit period nor increased competency associated with the higher number of required practice hours. However, the 12-month nighttime and 6-month passenger restrictions were found to be associated with annual savings of 55 and 816 fatal/injury crashes, respectively.
                Finding no overall impact of the 1998 GDL enhancements was not surprising given findings of an earlier survey suggesting that California teens and parents were largely already practicing program requirements prior to implementation and were not fully complying with the program requirements afterwards. Though the observed crash savings associated with the restrictions were of modest size, this is the first study to evidence a direct positive impact of the passenger restriction component of GDL programs. Larger reductions could be realized if the nighttime restriction started earlier and parents/law enforcement could be motivated to better enforce these restrictions.
                The findings provide support for passenger and nighttime restriction components of GDL programs. Graduated drivers license (GDL) programs have been shown to reduce motor vehicle fatalities among 15- to 17-year-olds. However, the 20 most rural states have been the least likely to enact more stringent GDL policies.
                Estimate the relationship of GDL programs and the number of traffic fatalities among 15- to 17-year-olds on rural interstate and noninterstate roadways.
                Analysis of 1992-2002 Fatality Analysis Reporting System data and a compendium of state laws using a conditional negative binominal regression model with full fixed effects to control for unobservable differences across states and years.
                Overall, GDL programs were associated with a 7.8% reduction in rural traffic fatalities among 15- to 17-year-olds. Virtually all of this reduction took place on noninterstate roadways. The most stringent GDL programs were associated with a nearly 22% reduction in this age group and were the only programs associated with reductions in fatalities among 15- to 17-year-old drivers.
                Rural states should consider enacting stringent GDL programs. Had the 19 of the 20 most rural states without such programs all adopted the most stringent GDL programs in 2002, the analysis suggests that 64 traffic deaths among 15- to 17-years-olds could have been prevented. To evaluate the four-year outcome of Michigan's graduated driver licensing (GDL) program, motor-vehicle crash data for 16-year-old drivers in 1996 (pre-GDL), and 1998-2001 (post-GDL) were analyzed.
                Relative risks and 95% confidence intervals for several crash types were computed, and pre-post-GDL population-based crash rates were compared. Reductions in crash risks among 16-year-olds previously found in 1998 and 1999 were generally maintained in 2000 and 2001.
                Reductions in crash risk among 16-year-olds from 1996 to 2001 were 29% for all, 44% for fatal, 38% each for nonfatal-injury and fatal-plus-nonfatal-injury, 32% for day, 31% for evening, 59% for night, 32% for single-vehicle, and 28% for multi-vehicle crashes. Even after adjusting for more general population-wide changes among drivers 25 years and older that might have contributed to changes in 16-year-old crash risk, reductions remained impressive (19% for all crashes in 2001).
                As one approach to reducing teenage motor-vehicle morbidity and mortality, GDL remains promising. Over the last 8 years, nearly every state has introduced graduated driver licensing (GDL) for teens. These new licensing procedures require teen drivers to advance through distinct stages where they are subject to a variety of restrictions (e.g., adult supervision, daytime driving, passenger limits). In this study, we present evidence on whether these restrictions have been effective in reducing traffic fatalities among teens. These evaluations are based on state-by-year panel data from 1992 to 2002. We assess the reliability of our basic inferences in several ways including an examination of contemporaneous data for older cohorts who were not directly affected by these policies. Our results indicate that GDL regulations reduced traffic fatalities among 15-17-year-olds by at least 5.6%. We also find that the life-saving benefits of these regulations were plausibly related to their restrictiveness. And we find no evidence that these benefits were attenuated by an increase in fatality risks during the full-licensure period available to older teens. On July 1, 1998, in an effort to ameliorate the problem of high teenage driver crash rates, California implemented a graduated driver licensing system (GDLS).
                Data on injury crashes of 16- and 17-year-old drivers from a pre-GDLS year were compared with data from two post-GDLS years. Per-capita crash rate ratios were adjusted for changes in crash rates of 25- to 34-year-old drivers, who were unaffected by the GDLS. Prevented numbers and 95% confidence intervals were estimated.
                Fatal or severe injury crash rates were significantly lower during each of the two post-GDLS years (adjusted rate ratios (RR)=0.72 and 0.83, for 2000 vs. 1997 and 2001 vs. 1997, respectively). Significant rate reductions were observed for all crash types, particularly for struck object (RR=0.71 and 0.80, for 2000 vs. 1997 and 2001 vs. 1997, respectively) and non-collision (RR=0.63 and 0.72, for 2000 vs. 1997 and 2001 vs. 1997, respectively). Minor injury crash rates were also lower during post-GDLS years (RR=0.87 and 0.90, for 2000 vs. 1997 and 2001 vs. 1997, respectively). Percent reductions were notably larger during the hours of the late night driving restriction (midnight-5 a.m.) (RR=0.79 and 0.87, for 2000 vs. 1997 and 2001 vs. 1997, respectively).
                The implementation of the California GDLS was followed by large reductions in the rate of injury-producing motor-vehicle crashes.
                This evaluation supports previous evidence that GDLS is an effective countermeasure to adolescent motor-vehicle crashes and their associated injuries. States with a traditional licensing system may prevent adolescent driver crashes by adopting a GDLS. Future studies should examine factors that influence teenager compliance with GDLS provisions and identify approaches to improving compliance. Graduated driver licensing (GDL) programs are being adopted in many states to address the high rate of motor vehicle fatalities among teens by requiring teenaged drivers to gain experience and maturity under conditions of relatively low crash risk before gaining full driving privileges.
                To evaluate the early impact of Michigan's GDL program on traffic crashes among 16-year-old drivers.
                Analysis of Michigan motor vehicle crash data from 1996 (before GDL program implementation) vs 1998 and 1999 (after GDL program implementation) for 16-year-olds, adjusting for trends among persons 25 years or older.
                Michigan's GDL program, instituted April 1, 1997, for teens younger than 18 years entering the driver license system, includes 3 licensure levels, each with driving restrictions and requirements to progress to the next level. Requirements include extended, supervised practice in the learning level, 2-phase driver education, and night driving restrictions in the intermediate level.
                Rates in 1996 vs 1998 and 1999 for all police-reported crashes; for fatal injury, nonfatal injury, and fatal/nonfatal injury combined crashes; for day, evening, and night crashes; for single-vehicle and multivehicle crashes; and for alcohol-related crashes.
                Overall, the rate of 16-year-old drivers (per 1000 population) involved in crashes declined from 154 in 1996 to 111 in 1999 (relative risk [RR], 0.72; 95% confidence interval [CI], 0.71-0.73). After adjusting for populationwide trends, the overall crash risk for 16-year-olds was significantly reduced in 1999 from 1996 by 25% (adjusted RR, 0.75; 95% CI, 0.74-0.77). There were also significant reductions for nonfatal injury and combined fatal and nonfatal crashes; for day, evening, and night crashes; and for single-vehicle and multivehicle crashes. Fatal crashes declined from 1996 to 1999, but not significantly (RR, 0.74; 95% CI, 0.49-1.14), and alcohol-related crashes continued at a low rate (RR, 1.01; 95% CI, 0.80-1.29).
                Analysis of the first 2 full calendar years following Michigan's GDL program implementation indicates substantial crash reductions among 16-year-olds. Future research is necessary to determine if these reductions are maintained and if other jurisdictions achieve similar results. The rate of motor vehicle crashes in the United States is higher among adolescent drivers than among any other age group. This study was conducted to determine whether implementation of a graduated driver's licensing program is associated with a reduced the rate of motor vehicle crashes and injuries involving adolescent driver.
                Time periods before and after establishment of Delaware's GDL program were compared. The one year "before" period spanned January 1, 1998, through December 31, 1998, and the 3-year "after" period spanned January 1, 2000, to December 31, 2002. Following enactment of the GDL program on July 1, 1999, we delayed data collection during the "after" period for 6 months to allow for full implementation of the program. Information was obtained for all Delaware registered drivers between ages 16 and 17 years were involved in motor vehicle crashes involving property damage or injury from 1998 to 2002. The rate of crashes involving property damage, EMS transport, injury, hospitalization, and death were determined pre- and post-GDL,. Length of hospitalization and hospital charges were compared, and the presence and age of passengers, along with time of day were determined.
                The total number of licensed 16- and 17-year-old drivers in Delaware was 14,320 during 1998 (the before period), 16,849 for 2000, 14,098 for 2001, and 14,276 for 2002, for a total of 45,223 licensed drivers studied during the after period. The proportion of hospitalizations, injuries, crashes involving property damage and total number of crashes involving registered 16- and 17-year-old drivers after GDL each decreased by at least 30%. In addition, this GDL program was associated with a reduction in nighttime crashes and in crashes involving cars with multiple passengers in comparison with the time period before GDL.
                Two years after implementation, the hospitalization rate, injury rate, and crash rate decreased significantly with enactment of the GDL program in the State of Delaware. The Delaware's GDL program appears successful in decreasing motor vehicle crashes and resultant injuries in adolescent drivers. The effectiveness of Iowa's graduated driver's licensing (GDL) program was evaluated for a 4-year period before and after implementation in 1999. Since some changes had occurred in the crash reporting format, changes in crash rates for younger drivers were compared to those for 35-44-year-old drivers (middle-age group of drivers) who were used as a control group. After implementation of GDL, the 14-, 16- and 17-year-old age groups experienced a greater decrease in crash rate than the middle-age control group while 15-year-old experienced a smaller decrease. This suggests that the crash rate for 15-year-old drivers may actually have increased when downward trends were adjusted for. Iowa's GDL program allows holders of the instruction permit to travel unaccompanied to and from school and school-endorsed activities after obtaining a minor school license. Fifteen-year-old with minor school licenses account for up to 26.7% of 15-year-old license holders yet represent up to 74.8% of 15-year-old drivers involved in crashes (depending on the year) from 1998 to 2004. As a result, 15-year-old drivers with minor school licenses are involved in 7.2-8.9 times more crashes, are 7.7 times more likely to have one or more sanctions, and are 4.8 times more likely to receive one or more moving convictions than their peers with a regular instruction permit. This help may explain why 15-year-old drivers did not seem to benefit from implementation of the GDL program in Iowa.
GDL is effective in reducing crash rates among young drivers, although the magnitude of the effect varies. The conclusions are supported by consistent findings, temporal relationship, and plausibility of the association. Stronger GDL programs (i.e. more restrictions or higher quality based on IIHS classification) appear to result in greater fatality reduction. Future studies should focus on which components and combination of components yield the greatest reductions.