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 |
|---|---|---|---|---|
| 240 | 2013/ 03 |
Teen and Senior Drivers – Report 240This report updates statistical information on California teen and senior drivers as published in earlier reports prepared by the California Department of Motor Vehicles: Teen Driver Facts (Huston, 1986), Senior Driver Facts (Huston & Janke, 1986), Teen and Senior Drivers (Romanowicz & Gebers, 1990; Gebers, Romanowicz, & McKenzie, 1993; Aizenberg & McKenzie, 1997 [with the Beverly Foundation]; and Janke, Masten, McKenzie, Gebers, & Kelsey, 2003). The information is meant to assist highway safety administrators in making program and policy decisions affecting teen and senior drivers, and may also be of use to the insurance industry, traffic safety researchers, and the general public. The report also summarizes international research on the driving safety and driving-related abilities of teen and senior drivers, and on crash countermeasures for these two groups. |
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| 244 | 2013/ 10 |
THE PROBLEM OF SUSPENDED AND REVOKED DRIVERS WHO AVOID DETECTION AT DUI/LICENSE CHECKPOINTSAlthough driver license suspension and revocation have been shown to improve traffic safety, suspended or revoked (SR) drivers who continue to drive—which appears to be the majority— are about three times more likely to be involved in crashes and to cause a fatal crash. The purpose of this study was to estimate the extent to which these drivers avoid detection at driving under the influence of alcohol or drugs (DUI) and license checkpoints because they illegally possess a physical license. Method. Law enforcement used electronic identification card readers at DUI/License checkpoints in Sacramento, California to record data for 13,705 drivers for purposes of estimating the extent to which SR drivers avoid detection. Differences in detection as a function of the reason for suspension or revocation were also investigated. Results. Although only 3% of the drivers contacted at the checkpoints were SR, about 41% of SR drivers were able to pass through undetected because they presented valid-looking licenses that should not have been in their possession. Drivers SR for DUI-related reasons were more likely to be detected, whereas those SR for failure to provide proof of financial responsibility were less likely to be detected. Discussion. The fact that many SR drivers were able to pass through DUI/License checkpoints undetected indicates a loophole in the traffic safety countermeasure system that needs to be addressed, because it undermines the efficacy of suspension/revocation and checkpoint countermeasures. Recommendations for improving licensing agency suspension orders and checkpoint screening methods are provided. |
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| 245 | 2013/ 11 |
PILOT STUDY OF A “HOT LIST” FOR THE SPECIFIC ENFORCEMENT OF REPEAT DRIVING UNDER THE INFLUENCE OFFENDERS WITH SUSPENDED OR REVOKED LICENSES: PROCESS EVALUATIONRepeat driving under the influence of alcohol or drug (DUI) offenders in California comprised 24.1% of all drivers involved in alcohol- or drug-related fatal crashes and 62.2% of those involved in alcohol- or drug-related injury crashes during 2010. Most DUI-prevention law enforcement operations (e.g., sobriety checkpoints) are intended to reduce DUI among the general driving population (i.e., general deterrence). Targeted enforcement efforts (i.e., specific deterrence) aimed at monitoring and ensuring DUI sanction and driver license action compliance among repeat DUI offenders has the potential to reduce their recidivism. The California Department of Motor Vehicles provided 15 law enforcement agencies with bimonthly “Hot Lists” of the driver license numbers of all suspended or revoked multiple DUI offenders for their use in conducting interventions for reducing driving and DUI recidivism among these offenders. This report summarizes the various enforcement processes and levels of commitment to using the lists, describes several barriers identified, and discusses problems in general associated with conducting targeted enforcement efforts. Hot List activities during the first year included 174 stops of offenders’ vehicles, 308 in-person checks of offenders’ compliances with probation requirements, 469 mailings of letters to offenders warning them not to drive, and 258 stakeouts of offenders at bars, residences, courts, or other locations. These activities resulted in 115 citations for driving on a suspended/revoked license, 129 vehicle impoundments, 23 DUI arrests, and 53 arrests for other reasons. The analysis identified barriers that contributed to limited use of the lists by some participating agencies—most resulting from funding constraints, officer training deficiencies, and the time and effort needed to verify requisite offender identities and residence addresses—and several tools and strategies that were developed by some agencies to more effectively use the Hot Lists. Recommendations are made for improving the dissemination and use of the Hot List, and for improving the reporting of Hot List-related activity |
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| 246 | 2014/ 01 |
2014 ANNUAL REPORT OF THE CALIFORNIA DUI MANAGEMENT INFORMATION SYSTEMIn this twenty-third annual legislatively-mandated report, 2011 and 2012 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, administrative 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 22 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 2011, who were referred, enrolled, and completed DUI programs are also presented. |
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| 248 | 2014/ 10 |
Cellular Phone Distracted Driving: A Review of the Literature and Summary of Crash and Driver Characteristics in CaliforniaThe present study reviews the literature on cell phone-distracted driving including the effectiveness of legislative efforts to reduce the behavior. It also reports results of descriptive analyses characterizing crashes and drivers involved in police-reported, cell phone-distracted crashes in California. Cell phone use in the U.S. is widespread and increasing. People tend to support legislative efforts to limit the use of cell phones while driving despite the fact that many continue to engage in the behavior. Empirical and observational research consistently shows a negative impact of cell phone use on driving performance and crash risk. The present study extracted data from the Statewide Integrated Traffic Records System database pertaining to crashes that occurred between 2003 and 2011 in California. These data were examined at two levels: crash and driver. Crash analyses revealed that most crashes did not involve inattention. When they did, non-cell phone inattention was more common than cell phone inattention and hand-held cell phone use was more commonly associated with crashes than hands-free. The most common primary crash factor for cell phone-related fatal/injury crashes was traveling at an unsafe speed. A larger percentage of cell phone-related fatal/injury crashes occurred during the workweek than on the weekend, and more occurred in the afternoon than in the morning or night. Driver analyses revealed that 21 to 30 year-old drivers accounted for the largest percentage of drivers involved in cell phone-related fatal/injury crashes. Males accounted for more cell phone-related fatal/injury crashes than females. Finally, drivers reported as using a cell phone at the time of fatal/injury crashes were more likely to be found at fault, and were slightly more likely to be found at fault than those using hands-free devices. |
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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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| 247 | 2015/ 01 |
General Deterrent Evaluation of the Ignition Interlock Pilot Program in CaliforniaThis study presents a general deterrence evaluation of the ignition interlock pilot program mandated by Assembly Bill 91 for the counties of Alameda, Los Angeles, Sacramento, and Tulare during the period of July 1, 2010 through January 1, 2016. This pilot program requires convicted first and repeat DUI offenders to install an IID on all vehicles they own or operate for a pre-specified time period in order to obtain a restricted, reissued, or reinstated driver’s license. The present study analyzes DUI conviction data from July 2007 through June 2013. The results indicate that IID installation rates among all DUI offenders increased dramatically in the pilot counties from 2.1% during the pre-pilot period to 42.4% during the pilot period. The results of the Auto-Regressive Integrated Moving Average (ARIMA) analyses show that the IID pilot program was not associated with a reduction in the number of first-time and repeat DUI convictions in the pilot counties. In other words, no evidence was found that the pilot program has a general deterrence effect. A follow-up study is being conducted to determine if the pilot program has any specific deterrence effects. It is recommended that any subsequent legislative action on this subject take into consideration the findings of this specific deterrence evaluation. This evaluation is anticipated to be completed in the fall of 2015. |
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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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| 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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| 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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