Effects of the California graduated driver licensing program

PROBLEM: 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). METHOD: 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. RESULTS: 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). SUMMARY: The implementation of the California GDLS was followed by large reductions in the rate of injury-producing motor-vehicle crashes. IMPACT ON INDUSTRY: 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.     

Driver license renewal by mail in California

Drivers under the age of 70 whose prior 4-year accident and conviction records showed no entries when examined 2 months prior to the date of expiration of their driver licenses were randomly assigned to either a group that renewed licenses in the normal manner or a group that was offered the opportunity to receive a 4-year license extension by mail. A related experiment involved comparing clean-record drivers of any age who were given a 2-year extension with a group of drivers required to renew in person. Examination of driver records 18 and 28 months subsequent to extension uncovered no deleterious effects of the program, while savings of roughly 3 million dollars annually are expected. Findings are tentative, however, until 4-year data can be collected. The report concludes that the extension program has been successful, that multiple extensions should be authorized and evaluated for drivers with continuing clean records, and that the present exclusion of drivers 70 and above does not appear to be defensible.     

An evaluation of the implementation of ignition interlock in California

Problem: This study evaluates the degree to which courts have implemented California's ignition interlock program, and surveys judges and district/city attorneys to identify barriers to implementing a successful interlock program. Method: There are three parts to the evaluation. In the first, a sample of drivers arrested for driving on a driving under the influence (DUI)-suspended driver license was examined to calculate the rate at which courts order interlocks for DUI-suspended drivers, as required by California law. The second part of the study used Department of Motor Vehicle (DMV) records to count the statewide rate of court-ignition interlock device (IID) orders across time and jurisdictions. The final part surveyed judges, district/city attorneys, and offenders installing an interlock to obtain information about their use of interlock, barriers to implementing an interlock program, and the effectiveness of the devices in preventing drinking and driving. Results: It was found that conviction rates for driving while suspended are low; that judges order interlocks for only a fraction of the convicted driving-while-suspended (DWS) offenders who should receive such an order; and that the majority of offenders who are ordered by the court to install an ignition interlock in their vehicle do not do so. Impact on Industry: Any successful interlock program will need to find a way to balance the inability of many offenders to pay for the devices, with the need for the industry to remain economically viable.     

Factors associated with fatal accident involvement among California drivers

The primary objectives of this study were to examine characteristics of drivers involved in fatal accidents and to determine if those drivers could be distinguished from California's general driving population on the basis of prior driving record. A sample of drivers involved in 1970–1971 fatal accidents was analyzed and compared to a sample of drivers from the general driving population during the same time period. Drivers who had been drinking prior to the accident, who were considered at-fault for the accident, or whose accident occurred at night were found to have worse prior driving records than other fatal accident-involved drivers. The results also indicated that, as a whole, drivers involved in fatal accidents had worse violation and/or accident records, as well as different demographic and license characteristics than drivers in the general population. The classification functions derived to predict fatal accidents, however, did not differ greatly from regression equations that have been constructed to predict total accidents. It was therefore concluded that prediction systems keyed to total accidents will, to a large extent, also identify high-risk fatal accident drivers.     

The impact of retail beverage service training and social host laws on adolescents' DUI rates in San Diego County,California

Introduction: Driving under the influence (DUI) citations are still a serious concern among drivers aged 16–20 years and have been shown to be related to increased risk of fatal and nonfatal crashes. A battery of laws and policies has been enacted to address this concern. Though numerous studies have evaluated these policies, there is still a need for comprehensive policy evaluations that take into account a variety of contextual factors. Previous effort by this research team examined the impact of 20 minimum legal drinking age–21 laws in the state of California, as they impacted alcohol-related crash rates among drivers under 21 years of age while at the same time accounting for alcohol and gas taxes, unemployment rates, sex distribution among drivers, and sobriety checkpoints. The current research seeks to expand this evaluation to the county level (San Diego County). More specifically, we evaluate the impact of measures subject to county control such as retail beverage service (RBS) laws and social host (SH) laws, as well as media coverage, city employment, alcohol outlet density, number of sworn officers, alcohol consumption, and taxation policies, to determine the most effective point of intervention for communities seeking to reduce underage DUI citations.

Methods: Annual DUI citation data (2000 to 2013), RBS and SH policies, and city-wide demographic, economic, and environmental information were collected and applied to each of the 20 cities in San Diego County, California. A structural equation model was fit to estimate the relative contribution of the variables of interest to DUI citation rates.

Results: Alcohol consumption and alcohol outlet density both demonstrated a significant increase in DUI rates, whereas RBS laws, SH laws, alcohol tax rates, media clusters, gas tax rates, and unemployment rates demonstrated significant decreases in DUI rates.

Conclusions: At the county level, although RBS laws, SH laws, and media efforts were found to contribute to a significant reduction in DUI rates, the largest significant contributors to reducing DUI rates were alcohol and gas taxation rates. Policy makers interested in reducing DUI rates among teenagers should examine these variables within their specific communities and consider conducting community-specific research to determine the best way to do so. Future efforts should be made to develop models that represent specific communities who are interested in reducing DUI rates among drivers aged 16–20 years.