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 |
|---|---|---|---|---|
| 111 | 1987/ 01 |
Accident and Conviction Rates of Visually Impaired Heavy Vehicle OperatorsThis study was designed to determine whether waiving the federal static acuity standard adversely impacted traffic safety. Drivers for whom the standard was waived could drive commercially only within California. Two-year accident and conviction rates of visually impaired commercial heavyvehicle operators (class 1 or 2 licensees) were compared to those of a sample of visually nonimpaired commercial heavy-vehicle operators. Nonimpaired drivers met current federal acuity standards (corrected acuity of 20/40 or better in both eyes), while impaired drivers had substandard static acuity and were classified as either moderately (corrected acuity between 20/40 and 20/200 in the worse eye) or severely (corrected acuity worse than 20/200 in the worse eye) impaired. California and total mileage estimates for Class 1 and Class 2 drivers obtained in a mailed questionnaire did not differ significantly between impairment groups. However, other potentially biasing factors remained and are discussed. Analysis of covariance, with age as a covariate, revealed that on subsequent two-year driver records the visually impaired drivers had significantly, and substantially, more total accidents and convictions than did the nonimpaired drivers. Severely impaired drivers had directionally worse driver records than did the moderately impaired drivers on three of the four traffic safety measures assessed, but these differences were not statistically significant. Study findings led to qualified support for the stricter federal standard, particularly in the case of the severely impaired heavy-vehicle operator. |
VI | |
| 207 | 2004/ 01 |
Teenage Driver Risks and InterventionsCalifornia teenage drivers aged 16-19-years-old have extremely high per capita and mileage-adjusted crash and traffic violation rates. This report summarizes the literature regarding the risk factors involved in their high crash rates, as well as the countermeasures that have been used in California and elsewhere to reduce their high crash risk. Although some portion of teenage crash involvements can be accounted for by poorer basic vehicle handling skills, the research suggests that it is young drivers’ immaturity and inexperience, and the resultant risk-taking, that contribute most to their increased crash risk. Certain driving conditions, such as nighttime driving and transporting young passengers, are particularly high risk for teen drivers. The higher crash rates for teens associated with the use of alcohol and drugs may mostly be the result of a general pattern of risky behavior. The countermeasures used to reduce the crash risk of teen drivers that are discussed in this report include driver improvement programs, driver education and training, special licensing programs for teens (provisional and graduated licensing), BAC limits, and curfew laws. |
VI | |
| 238 | 2012/ 09 |
ESTIMATION OF FATAL CRASH RATES FOR SUSPENDED/REVOKED AND UNLICENSED DRIVERS IN CALIFORNIAThis study used a quasi-induced exposure (QIE) analysis technique to estimate annual fatal crash involvement rates for S/R, unlicensed, and validly licensed drivers in California from 1987 through 2009 using fatal crash data obtained from National Highway Traffic Safety Administration’s Fatality Analysis Reporting System (FARS) and California Department of Highway Patrol’s Statewide Integrated Traffic Records System (SWITRS). The annual fatal crash involvement ratios range from 0.81 to 0.91 for validly licensed drivers, 1.44 to 4.29 for S/R drivers, and 1.60 to 3.50 for unlicensed drivers, respectively, over the 23-year time period studied. The annual at-fault overinvolvement rates for S/R and unlicensed drivers relative to validly licensed drivers range from 1.57 to 4.93 for the S/R group and from 1.84 to 4.10 for the unlicensed group. Although the annual rates fluctuate, S/R and unlicensed drivers were overinvolved as at-fault drivers in fatal crashes every year relative to validly licensed drivers. The fatal crash involvement ratios obtained for all years combined (1987 through 2009) are 0.86 for validly licensed drivers, 2.23 for S/R drivers, and 2.34 for unlicensed drivers. The at-fault overinvolvement rates for the S/R and unlicensed groups, relative to the validly licensed group, are 2.60 and 2.73, respectively, for this 23-year period. The study results provide strong evidence that S/R and unlicensed drivers are much more hazardous on the road than are validly licensed drivers. Compared to licensed drivers, those who drive without a valid license are nearly three times more likely to cause a fatal crash relative to their exposure. The study findings strongly justify the use of countermeasures, including vehicle impoundment, to control S/R and unlicensed drivers and to reduce crashes caused by these drivers. |
VI | |
| 241 | 2013/ 02 |
EVALUATION OF A CONTACT LETTER TO INCREASE LICENSURE AMONG IMPROPERLY LICENSED CALIFORNIA MOTORCYCLE OWNERSThis report presents results of an evaluation of a pilot program intended to increase licensure among improperly licensed California motorcycle owners. The intervention used in this pilot program involved mailing an official DMV contact letter to owners of currently-registered motorcycles who were not properly licensed to ride two-wheeled vehicles. This correspondence informed the recipient of the legal consequences of riding without proper licensure, and provided information regarding how to obtain a motorcycle license in California. Half of the improperly licensed motorcycle owners (n = 33,068) were randomly assigned to be mailed the contact letter. The remainder (n = 32,698) served as a noletter control group. The 33-month subsequent-to-mailing license status and 18-month subsequent-to-mailing driver records for participants in these two groups were compared to determine the effect of the letter on motorcycle licensure, crashes, and violations. The results indicate that the contact letter increased motorcycle licensure among most age groups of owners, but did not affect crash involvements or traffic violations. The contact letter increased the number of previously unlicensed owners who became legal motorcycle operators without increasing their crash or traffic violation rates, but at a total net cost of $25.81 per additional owner who became properly licensed as a result of sending the letters. While the letter treatment significantly increased the motorcycle licensure rate, the overwhelming majority of treated owners in the present study (85.5%) remained improperly licensed to operate two-wheeled vehicles on public roadways, which is consistent with the results from a similar study in Maryland (Braver et al., 2007). Given the relatively low cost of treatment, the increase in motorcycle licensure associated with the letter, and the traffic-safety neutral outcomes, it is recommended that future use of a contact letter for improperly licensed owners be considered if the value of bringing owners into legal licensing status is deemed to be worth the cost of treatment. Future letters may be more effective if they are specifically tailored to the demographic characteristics (e.g., age and sex) of the unlicensed owners. |
VI | |
| 242 | 2013/ 02 |
CHANGES IN DRIVER CANNABINOID PREVALENCE ASSOCIATED WITH IMPLEMENTING MEDICAL MARIJUANA LAWS IN 14 U.S. STATESThis study’s objective was to investigate whether implementing medical marijuana laws was associated with changes in cannabinoid prevalence among drivers involved in fatal crashes in California and 13 other states with medical marijuana laws implemented before 2010. Time series ARIMA analyses were used to calculate stateby-state estimates of the percentage-point change in cannabinoid prevalence among fatal-crash-involved drivers associated with implementation or modification of medical marijuana laws. The implementation of medical marijuana laws was found to be reliably associated with increased cannabinoid prevalence in only three states: California, with a 2.1 percentage-point increase in the percentage of all fatal-crash-involved drivers who tested positive for cannabinoids (1.1% pre vs. 3.2% post, which represents a 196% increase in cannabinoid prevalence relative to the pre-law level) and a 5.7 percentage-point increase (1.8% vs. 7.5%, or a 315% increase) among fatally-injured drivers; Hawaii, with a 6.0 percentage-point increase (2.5 vs. 8.5, or a 235% increase) for all drivers and a 9.6 percentage-point increase (4.9% vs. 14.4%, or a 196% increase) among fatally-injured drivers; and Washington, with a 3.4 percentage-point increase (0.7% vs. 4.1%, or a 455% increase) for all drivers and a 4.6 percentage-point increase (1.1% vs. 5.7%, or a 432% increase) among fatally-injured drivers. The increases in all three states were stable step increases, meaning that the prevalence increased to a new level in these states and remained relatively flat subsequently. No relation between the post-law cannabinoid prevalence change estimates and the ease of marijuana access rankings was found. |
VI | |
| 38 | 1971/ 09 |
The Young Driver Follow-up Study: An Evaluation of the Role of Human Factors in the First Four Years of DrivingTo collect biographical and driving-record data in order to provide evidence for evaluating three approaches to reducing the high accident rate among teenagers: (1) raising the licensing age to 18; (2) identifying the "accident prone" driver; and (3) improving driving via formal driving education and training. |
VI | |
| 42 | 1973/ 05 |
Physically Handicapped Drivers: A Comparative Study of Driver RecordsThis study was conducted at the request of California State Assemblyman John P. Quimby, who was interested in the driving record of handicapped persons with loss of, or limited control of, one or more of their limbs. This study was expected to be useful in evaluating California's driver licensing policy and in providing some guidance to insurance companies in establishing premiums for handicapped drivers. California's policy has been to license physically handicapped persons who meet the same standards on the written and on-road examinations as non-handicapped persons. The purpose of this study was to determine whether or not handicapped drivers have accident records different from those of non-handicapped drivers, and consequently, whether there is any basis for differential licensing standards or insurance premiums. |
VI | |
| DOT HS-806688 | 1984/ 12 |
Development of Knowledge and Performance Tests for Heavy Vehicle Operators: Volume I, Development and Field TestThis report describes the development and evaluation of the Truck Operator Qualifications Examination (TORQUE) consisting of the following tests: 1. Truck Operator Road Test (TORT); 2. Truck Operator Skill Test (TOST); 3. Truck Operator Manual (TOM); 4. Truck Operator Knowledge Examination (TOKE); 5. Truck Operator Pretest (TOP); 6. Truck Operator Defects Examination (TODE). The field-validation phase of the project was done in Los Angeles, California under a subcontract to the California Department of Motor Vehicles. |
VI | |
| NRN078 | 1989/ 12 |
Development and Evaluation of a Risk Assessment Strategy for Medically Impaired DriversDetailed AnalysisTo further evaluate a risk-assessment strategy for drivers with physical or mental (P&M) conditions. |
VI | |
| NRN086 | 1996/ 01 |
The Relationship Between Age-Related Functional Disability and Road SafetyTo define the relationship between aging and safe driving for use by General Motors and NHTSA in establishing research funding priorities. |
VI |