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.
Studies & Reports Sections
Studies and reports are assigned to a Section that best describes the type of report. Click on a section title below to see a short description.
I. Driver Education & Training Studies
II. Driver Licensing Screening Studies
III. Studies on Improvement and Control of Deviant Drivers
IV. Basic Research & Methodological Studies: Driver Performance, Accident Etiology, Prediction Models, and Actuarial Applications
V. Driver Licensing / Control Systems & Safety Management Studies
VI. Studies on Special Driver Populations
VII. Miscellaneous Studies & Reports
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.
| Report ID | Date Published | Title | Section | Links |
|---|---|---|---|---|
| 259 | 2020/ 01 |
2018 Annual Report of the California DUI Management Information SystemIn this twenty-seventh annual legislatively-mandated report, 2015 and 2016 driving under the influence of alcohol and/or drugs (DUI) data from diverse sources were compiled and cross-referenced for the purpose of developing a single comprehensive DUI data reference and monitoring system. This report presents crosstabulated information on DUI arrests, convictions, postconviction sanctions, driver license suspension/revocation actions, and on drivers in alcohol-or drug-involved crashes. In addition, this report provides 1-year proportions of DUI recidivism and crash rates for first and second DUI offenders arrested in each year over a time period of 26 years. Also, the long-term recidivism curves of the cumulative proportions of DUI reoffenses are shown for all DUI offenders arrested in 2005. An analysis was conducted to evaluate if referrals to the 9-month DUI program were associated with reductions in 1-year subsequent DUI incidents and crashes when compared to referrals to the 3- month DUI program among first DUI offenders. The proportions of convicted first and second DUI offenders arrested in 2015, who were referred, enrolled, and completed DUI programs are also presented. Additionally, the numbers and percentages of DUI offenders who installed ignition interlock devices are presented by county and DUI offender status. |
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| 258 | 2021/ 08 |
AB 2499: A Traffic Safety Evaluation of California’s Traffic Violator School Masked Conviction ProgramThe negative traffic safety impact of California’s prior traffic violator school (TVS) citation dismissal policy is well documented in past departmental TVS evaluations. Using advanced inferential statistical techniques, the current study evaluated the substantive changes to California’s Traffic Violator School program as required by California Assembly Bill 2499 (Chapter 599, Statutes of 2010). The program changes implemented by AB 2499 appear to be associated with a specific deterrent effect as evidenced by a reliable and statistically significant reduction in subsequent traffic crashes and convictions of those receiving a masked TVS conviction as opposed to a countable conviction. Although the results suggest that this relationship exists primarily among TVS drivers with less elevated prior records, the change in status from a TVS citation dismissal to a TVS masked conviction has reduced the negative traffic safety impact of the TVS citation dismissal policy in effect prior to the implementation of AB 2499. Several recommendations are offered to enhance the positive traffic safety impact of the TVS program by further combining its educational elements with the Department’s post-license control program by way of the Negligent Operator Treatment System. |
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| 257 | 2018/ 10 |
2017 Annual Report of the California DUI Management Information SystemIn this twenty-sixth annual legislatively-mandated report, 2014 and 2015 driving under the influence of alcohol and/or drugs (DUI) data from diverse sources were compiled and cross-referenced for the purpose of developing a single comprehensive DUI data reference and monitoring system. This report presents crosstabulated information on DUI arrests, convictions, postconviction sanctions, driver license suspension/revocation actions, and on drivers in alcohol- or drug-involved crashes. In addition, this report provides 1-year proportions of DUI recidivism and crash rates for first and second DUI offenders arrested in each year over a time period of 25 years. Also, the long-term recidivism curves of the cumulative proportions of DUI reoffenses are shown for all DUI offenders arrested in 2005. An analysis was conducted to evaluate if referrals to the 9-month DUI program were associated with reductions in 1-year subsequent DUI incidents and crashes when compared to referrals to the 3- month DUI program among first DUI offenders. The proportions of convicted first and second DUI offenders arrested in 2014, who were referred, enrolled, and completed DUI programs are also presented. Additionally, the numbers and percentages of DUI offenders who installed ignition interlock devices are presented by county and DUI offender status. |
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| 256 | 2018/ 10 |
2016 Annual Report of the California DUI Management Information SystemIn this twenty-fifth annual legislatively-mandated report, 2013 and 2014 driving under the influence of alcohol and/or drugs (DUI) data from diverse sources were compiled and cross-referenced for the purpose of developing a single comprehensive DUI data reference and monitoring system. This report presents cross-tabulated information on DUI arrests, convictions, court sanctions, license suspension/revocation actions, and alcohol- or drug-involved crashes. In addition, this report provides 1-year proportions of DUI recidivism and crash rates for first and second DUI offenders arrested in each year over a time period of 24 years. Also, the long-term recidivism curves of the cumulative proportions of DUI reoffenses are shown for all DUI offenders arrested in 1994. Two analyses were conducted to evaluate if referrals to DUI programs were associated with reductions in 1-year subsequent DUI incidents and crashes among those convicted of the reduced charge of alcohol- or drug-related reckless driving, and if referrals to the 9-month DUI program were associated with reductions in 1-year subsequent DUI incidents and crashes when compared to referrals to the 3-month DUI program among first DUI offenders. The proportions of convicted first and second DUI offenders arrested in 2013, who were referred, enrolled, and completed DUI programs are also presented. |
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| 255 | 2018/ 06 |
An Evaluation of The Effect of Gaps In Licensure On Traffic Safety Outcomes Subsequent to RenewalAbsent 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). |
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| 254 | 2017/ 07 |
Predicting Traffic Crash Involvement Using Individual Driving Habits, Driving Record, and Territorial Risk IndicesThis study surveyed a sample of California drivers to determine their habits and opinions on selected traffic issues. The study also assessed the importance of exposure and territorial risk indices as predictors of traffic crashes beyond that of driver record factors. The information provided in this report is intended to assist traffic safety administrators and lawmakers in improving services and in developing more effective driver safety programs. |
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| 252 | 2017/ 02 |
Crash Risks of Drivers with Physical and Mental (P&M) Conditions and Changes in Crash Rates Over TimeThis study reviews recent research evaluating traffic safety in individuals diagnosed with epilepsy, syncope, dementia/Alzheimer’s Disease, diabetes, and sleep disorders. Additionally, this study evaluates the crash risk of drivers identified as having a physical or mental condition which may affect their ability to drive safely, and compared these findings to previous DMV reports which evaluated crash risk in this population. Research has repeatedly demonstrated that these drivers have a higher crash rate relative to the general population of drivers (Janke, Peck, & Dryer, 1978; Janke, 1993; Mitchell & Gebers, 2001). Crash rates for all drivers referred to DMV for a medical condition in the 2007 calendar year, and were assigned a P&M code (alcohol, drugs, lack of skill, lapses of consciousness, mental condition, or physical conditions) on their driving record were compared to crash rates for the general population of drivers. The mean crash rate for each of the P&M groups was higher than both the general population of drivers (7 per 100 drivers) and males under 25 (10 per 100 drivers). Relative to prior DMV studies, mean crash rates for drivers with a P&M designation of drug addiction, lapses of consciousness, and mental condition had dropped. A logistic regression where age and sex were controlled demonstrated an increased crash risk for each of the P&M conditions ranging from 2.8 to 13.3 times higher than the general population, with individuals with a mental condition having the lowest odds ratio and lack of skill having the highest odds ratio. The odds ratios for all conditions were higher than observed in prior DMV studies. One reason for this increase was an observed decrease in crash rates for the general population of drivers which did not correspond to a drop in crash rates for drivers with a P&M condition. Future research needs to evaluate the specific medical conditions within each P&M designation to better understand the relationship between medical conditions and crash risk in this population of drivers. |
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| 251 | 2016/ 06 |
AB 91: Specific Deterrent Evaluation of the Ignition Interlock Pilot Program in CaliforniaThis study presents an evaluation of the specific deterrence effects of California’s ignition interlock pilot program mandated by AB 91 to operate in four California counties — Alameda, Los Angeles, Sacramento, and Tulare — from July 1, 2010 to January 1, 2016. This study is a follow-up to an earlier legislatively-mandated general deterrence evaluation of AB 91’s IID pilot program. The purpose of the present study is to evaluate the specific deterrent capacity of AB 91’s IID pilot program, that is, whether it led to reductions in DUI recidivism and crashes among DUI offenders. Results show that, while the AB 91 pilot program can be associated with reductions in DUI recidivism among specific DUI offender groups, it is also associated with an increase in subsequent crashes among all first DUI offenders in AB 91 pilot counties and among all DUI offenders who installed an IID and obtained an AB 91 IID-restricted driver license. Although the reduction in DUI recidivism provides evidence of benefits associated with IID restrictions, the increased crash risks associated with the AB 91 pilot program suggest that additional investigation and research could be beneficial. Inclusion of information regarding crash responsibility (i.e. at-fault/not-at-fault), alcohol involvement, or severity level (i.e. fatal/injury crashes vs property-damage only crashes) may provide further insight. The report recommends to (1) evaluate California's incentive IID program mandated under Senate Bill 598, (2) conduct and report to the Legislature a quantitative evaluation of the efficacy of current or potential DUI countermeasures (including IIDs) and their combined use, (3) explore the option of using IIDs as an “alcohol-abstinence-compliance” monitoring tool, as part of a modified version of the traditional DUI court model, and (4) convene a task force to develop recommendations for strengthening components of California's comprehensive DUI countermeasure system. |
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| 250 | 2015/ 01 |
2015 Annual Report of the California DUI Management Information SystemIn this twenty-fourth annual legislatively-mandated report, 2012 and 2013 driving under the influence of alcohol and/or drugs (DUI) data from diverse sources were compiled and cross-referenced for the purpose of developing a single comprehensive DUI data reference and monitoring system. This report presents crosstabulated information on DUI arrests, convictions, court sanctions, administrative actions, and alcohol- or druginvolved crashes. In addition, this report provides 1-year proportions of DUI recidivism and crash rates for first and second DUI offenders arrested in each year over a time period of 23 years. Also, the long-term recidivism curves of the cumulative proportions of DUI reoffenses are shown for all DUI offenders arrested in 1994. Two analyses were conducted to evaluate if referrals to DUI programs were associated with reductions in 1-year subsequent violations and crashes among those convicted of the reduced charge of alcohol- or drug-related reckless driving, and if referrals to the 9-month DUI program were associated with reductions in 1-year subsequent violations and crashes when compared to referrals to the 3-month DUI program among first DUI offenders. The proportions of convicted first and second DUI offenders arrested in 2012, who were referred, enrolled, and completed DUI programs are also presented. |
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| 249 | 2014/ 10 |
Evaluation of Law Enforcement Use of Driver License Card Readers to Improve Detection of Suspended and Revoked Drivers at DUI/License CheckpointsIntroduction. Driving privilege suspension and revocation are known to improve traffic safety, but research suggests the majority of suspended or revoked (SR) drivers continue to drive while they are SR. These drivers are about three times more likely to be involved in crashes and to cause a fatal crash. In most U.S. states, drivers arrested for driving under the influence of alcohol or drugs (DUI) are subject to immediate driver license (DL) card confiscation by law enforcement. Drivers SR for other reasons are typically mailed notices directing them to surrender their DL cards to the licensing agency, yet they frequently do not comply. At DUI checkpoints in California, and many other U.S. states, law enforcement officers briefly inspect drivers’ DL cards and check for signs of intoxication. Hence, such checkpoints are deemed DUI/License status checkpoints. Previous research found that about 41% of SR drivers contacted at such checkpoints avoided detection for SR driving because they illegally retained possession of their DL cards. In this study, DL card readers with the capacity to identify and alert officers to drivers with SR statuses were used at the checkpoints. The purpose was to evaluate the utility of implementing this type of technology on a broader scale. Method. Checkpoint police officers used DL card readers that contained lists of SR drivers that would alert if a card was scanned that matched a DL number on the list. Data for 13,530 drivers were recorded. Subsequently, license statuses of contacted drivers were verified and compared to checkpoint citation records. Results. About 3% (n=384) of drivers contacted at the checkpoints were SR. Seventy-one percent of them were detected and cited for driving while SR. There were no differences in detection rate as a function of the suspension/revocation reasons. Significant differences were found in detection rate as a function of whether drivers’ DL numbers were on the SR list. Conclusion. SR drivers’ ability to pass undetected through DUI/License checkpoints weakens both the specific and general SR driving deterrence of checkpoints, and may diminish the effectiveness of suspension and revocation for reducing the crash risk posed by problem drivers. These findings show that despite technical limitations, a list-based DL card reader can improve the detection rate of SR drivers by law enforcement. Future studies that evaluate scanning technologies capable of real-time license validity verification are warranted. |
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