Research Studies & Reports

DMV’s Research & Development Branch has been conducting research and producing studies and reports since the 1950s. Research & Development reports help DMV to measure the impact of new laws on making drivers safer. We also identify areas where we can improve our processes, explore new approaches to solving existing problems, and branch out into new opportunities to serve you better. 

Request printed copies of studies and reports by mail at:

Department of Motor Vehicles
Research and Development Branch
2415 1st Ave. Mail Station: F-126
Sacramento, CA 95818
(916) 914-8125

Please include the report number, the number of copies requested, and your name, address, and phone number.

393 Results

Report ID Date Published Title Section Links
181 1998/ 12

An Evaluation of the Impact of California’s Driving PerformanceEvaluation Road Test on Traffic Accident and Citation Rates

By: Michael A. Gebers, Patricia A. Romanowicz, & Robert A. Hagge

This evaluation is the final stage of a project to develop and evaluate the driving performance evaluation(DPE) drive test for possible statewide implementation in California. This study and earlier studies in theseries are part of a more extensive effort by the department to increase the competency of Californiamotorists by improving the driver licensing process. The DPE is currently being used in over 60 fieldoffices in southern California.The effect of the DPE on accident and citation rates was determined by comparing driving records for asample of applicants taking the DPE with those of a sample of applicants taking the current drive test bothbefore and after implementation of the DPE.Logistic regression analysis was used to compare the crash and citation rates of the groups during the 2years immediately following driver license application. The findings failed to substantiate any reduction inaccident involvements or traffic law violations resulting from implementation of the program. However,there is no question that the DPE is a more reliable and content-valid test. Therefore, it is recommendedthat the DPE road test be expanded to all offices in the state.

II
104 1986/ 01

An Evaluation of the Impact of a Warning Letter for First-Time DUI Offenders (Volume 6 of “An Evaluation of the California Drunk Driving Countermeasure System”)

By: Gary Arstein-Kerslake

To develop, implement, and evaluate a package consisting of a warning letter and pamphlet suitable for the first-DUI offender.

III
210 2004/ 09

AN EVALUATION OF THE EFFECTIVENESS OF IGNITION INTERLOCK IN CALIFORNIA

By: David J. DeYoung, Helen N. Tashima, and Scott V. Masten

This study is one of two studies of ignition interlock in California mandated by the California Legislature (AB 762). The first study, published in 2002, was a process evaluation that examined the degree to which ignition interlock has been implemented in California. This current study is an outcome evaluation that examines the effectiveness of ignition interlock in reducing alcohol-related crashes and convictions, and crashes overall (alcohol and nonalcohol). The results of the study show that interlock works for some offenders in some contexts, but not for all offenders in all situations. More specifically, ignition interlock devices work best when they are installed, although there is also some evidence that judicial orders to install an interlock are effective for repeat DUI offenders, even when not all offenders comply and install a device. California’s administrative program, where repeat DUI offenders install an interlock device in order to obtain restricted driving privileges, is also associated with reductions in subsequent DUI incidents. One group for whom ignition interlock orders do not appear effective is first DUI offenders with high blood alcohol levels.

V
217 2005/ 09

AN EVALUATION OF THE EFFECTIVENESS OF IGNITION INTERLOCK IN CALIFORNIA

By: David J. DeYoung, Helen N. Tashima, and Scott V. Masten

This study is one of two studies of ignition interlock in California mandated by the California Legislature (AB 762). The first study, published in 2002, was a process evaluation that examined the degree to which ignition interlock has been implemented in California. This current study is an outcome evaluation that examines the effectiveness of ignition interlock in reducing alcohol-related crashes and convictions, and crashes overall (alcohol and nonalcohol). The results of the study show that interlock works for some offenders in some contexts, but not for all offenders in all situations. More specifically, ignition interlock devices work best when they are installed, although there is also some evidence that judicial orders to install an interlock are effective for repeat DUI offenders, even when not all offenders comply and install a device. California’s administrative program, where repeat DUI offenders install an interlock device in order to obtain restricted driving privileges, is also associated with reductions in subsequent DUI incidents. One group for whom ignition interlock orders do not appear effective is first DUI offenders with high blood alcohol levels.

V
146 1995/ 01

AN EVALUATION OF THE EFFECTIVENESS OF CALIFORNIA DRINKING DRIVER PROGRAMS

By: David J. DeYoung

There has been longstanding interest in determining which sanctions work best to reduce drunk driving. This study, mandated by the California Legislature (SB 1344) and funded by the California Department of Alcohol and Drug Programs (DADP), examined the degree to which first offender, SB 38 and 30-month drinking driver programs (DDPs) in California reduced drunk driving recidivism, relative to other sanctions, such as driver license suspension. Based on the findings from this study, as well as those from prior research, this report recommends combining alcohol treatment with driver license actions as the best strategy for reducing drunk driving recidivism and enhancing overall traffic safety.

V
255 2018/ 06

An Evaluation of The Effect of Gaps In Licensure On Traffic Safety Outcomes Subsequent to Renewal

By: Kevin Limrick

Absent a progressive physical or mental condition, motorists in California are permitted to renew their driver license without submitting to a skills test. This policy applies regardless of how long a customer’s license has been expired. Given a lack of published research on the retention of motor skills required of driving, the current study was designed to evaluate the effect of a “gap” in licensure on one’s ability to safely operate a motor vehicle. More specifically, it sought to determine whether a gap in a customer’s licensing history was associated with crashes and / or convictions subsequent to renewal. To that end, the Department’s Driver License Master File was used to identify motorists in California who had a clearly defined gap at some point during their licensing history. These customers were then placed into one of three study groups based upon the length of time it took for them to relicense: 1 to 30 days (n = 6,135), 31 to 365 days (n = 4,688), or greater than 365 days (n = 1,973). A fourth group of drivers, all of whom had not experienced a gap in their licensing history (i.e., those who renewed early), was also identified to serve as a type of quasi-experimental control group. These analyses found that drivers who had a gap of at least 1 year had the same odds of incurring at least one post-renewal conviction as did drivers who renewed early. Logistic regression and Cox proportional hazards models also indicated that gap duration was not a significant predictor of post-renewal crash involvement; drivers in this study were equally likely to experience a post-renewal crash, regardless of how long they were unlicensed. Based on the findings of this report, recommendations are made to maintain current DMV policy and not integrate skills testing as part of the renewal process, absent additional information indicating potential issues of concern (e.g., a progressive vision disorder).

II
44 1973/ 12

An Evaluation of the Drive Test as an Examination Requirement for Drivers Previously Licensed in Another State

By: David M. Harrington

To determine if waiving the drive test for original applicants previously licensed in another state would be detrimental to their driving records.

II
107 1986/ 05

An Evaluation of the California Habitual Traffic Offender Law

By: Clifford J. Helander

To evaluate the California habitual traffic offender law (AB 3529 - Mountjoy) interms of: (1) the number of habitual traffic offenders (HTO) identified, (2) their prosecution and conviction rates, and (3) the degree of traffic safety risk posed by HTOs

III
112 1987/ 12

An Evaluation of the California Drunk Driving Countermeasure System: An Overview of Study Findings and Policy Implications

By: Raymond C. Peck

To summarize the results and policy implications of seven-part study entitled An Evaluation of the Countermeasure System. a major federally funded California Drunk Driving

III
52 1976/ 04

An Evaluation of the California Driver Knowledge Test and the University of Michigan Item Pool

By: David W. Carpenter

To evaluate both the written DMV driver licensing test and a large sample of driver knowledge test items selected from the University of Michigan's Highway Safety Research Institute (HSRI) item pool.

II