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CARS-DUI Assessment Project

Computerized Assessment and Referral System (CARS)

Research has found that repeat DUI offenders commonly suffer from a number of mental health disorders (e.g., anxiety disorders, post-traumatic stress disorder, depression, bipolar disorder, conduct disorder) in addition to their substance use issues. In one study, in addition to a lifetime alcohol disorder, 41% of the participants had a drug-related disorder and 45% had a major mental disorder that was not alcohol or drug-related.

The basis for the Computerized Assessment and Referral System (or CARS project) was the recognition of the high level of psychiatric co-morbidity in DUI populations. Historically, treatment of this offender population has consisted of alcohol education or interventions that focus solely on alcohol or other substance use disorders. Screening for mental health issues in addition to substance use is not always available or performed within DUI treatment programs. CARS was developed to fill this void as its primary purpose is to identify mental health issues that might influence DUI behaviors, facilitate additional treatment for those issues and possibly reduce future recidivism.

Developed by the Division on Addiction, Cambridge Health Alliance, a teaching affiliate of Harvard Medical School, with initial support by the National Institute on Alcohol Abuse and Alcoholism (NIAAA) and ongoing funding from, CARS is a standardized mental health assessment tool, based on the World Health Organization’s Composite International Diagnostic Interview (or CIDI), that runs on free open source software.

How does CARS work?

  • Asks about signs and symptoms of mental health issues both within the past year and lifetime.
  • Identifies specific mental health disorders for which an offender is at-risk.
  • Generates a report that informs the user about a client’s treatment needs and provides appropriate ZIP code based referrals.
  • Can be used in three formats:
    • CARS screener (15-40 minutes)
    • Self-administered CARS screener (15-40 minutes)
    • Full CARS assessment (1-2 hours)

CARS has the following benefits that make it an ideal tool for practitioners:

  • Developed specifically for a DUI offender population;
  • Provides immediate diagnostic information for up to 15 major psychiatric disorders;
  • Provides geographically and individually targeted referrals to appropriate treatment services;
  • Generates user-friendly reports at the click of a button;
  • Informs supervision and treatment decisions;
  • Runs on free open source software; and,
  • Can be used by non-clinicians. supports the use of comprehensive assessment for substance use and mental health disorders among the DUI offender population as well as referrals to appropriate treatment interventions tailored to individual risks and needs.

CARS has received widespread support from the Governor’s Highway Safety Association, American Probation and Parole Association, Emergency Medicine Foundation, Cambridge Health Alliance, Harvard Medical School and Harvard School of Public Health.

CARS Implementation Trial Results:

Following the 2013 usability trials a full implementation study was completed in 2015 among first offenders and repeat offenders in two Massachusetts-based DUI treatment programs. The randomized control trials assessed the usability of the comprehensive CARS instrument along with two shorter versions (i.e., screeners). Data analyses from these implementation trials validated the self-administered CARS screener, interviewer-administered CARS screener and comprehensive CARS tool as successful assessment tools.

In October Dr. Howard Shaffer, lead researcher and the Dr. Morris E. Chafetz Professor in Psychiatry in the Field of Behavioral Sciences at Harvard Medical School and Dr. Sarah Nelson, Associate Director of Research, Harvard Medical School, Division on Addiction, The Cambridge Health Alliance, presented the preliminary results of the implementation trials of the CARS tool to the National Highway Traffic Safety Administration (NHTSA) and the National Institute on Alcohol Abuse and Alcoholism (NIAAA). CARS is designed to identify mental health issues in addition to substance use disorders among DUI offenders. Identifying the issues that influence DUI behavior is the first step toward intervening to reduce the impact of DUI and improving offenders’ chances of rehabilitation.

  • Implementation trials took place at two Massachusetts DUI programs
  • Tested comprehensive CARS vs. CARS screener as well as self-administered CARS screener vs. interviewer-administered CARS screener
  • Continued evidence of comorbidity in the repeat DUI population, particularly anxiety-related disorders
  • Full CARS provides diagnostic information
  • Screening results did not differ significantly by condition, with the exception of conduct disorder among DUI offenders in the self-administered trial setting
  • CARS screener does a very good job of identifying substance use disorders
  • Results from self-administered screener do not differ fundamentally from those for the interviewer-administered screener
  • Six month follow-up with DUI offenders currently underway to measure alcohol and drug use, treatment, lapses and relapses, probation violations, behavioral changes and mental health check-in – results will be available in 2016


CARS - NHTSA October cover page


CARS Presentation at NHTSA – October 2015

CARS Next Steps:

Currently, CARS identifies DUI risk based on known predictors from the research literature, expanding the CARS program will enable data to be collected that will allow researchers to modify the risk scale using empirical data to link specific mental health profiles to recidivism risk. Additionally, moving beyond post-conviction DUI programs – time between sentencing and DUI treatment – would represent an earlier assessment and intervention opportunity among at-risk populations. Funding in 2016 and 2017 will support:

  • Program Expansion: 6 pilot sites throughout the US
    • IMPACT DWI Program (Milwaukee, WI)
    • Isanti County probation; Judge James Dehn (Cambridge, MN)
    • Lackawanna/Susquehanna Office of Drug and Alcohol Programs; Judge Michael Barrasse (Scranton, PA)
    • Laramie County DUI Court (Cheyenne, WY)
    • San Joaquin County Monitoring Court Program; Judge Richard Vlavianos (Stockton, CA)
    • South St. Louis County DWI Court and probation; Judge Shaun Floerke (Duluth, MN)
  • Finalizing CARS for distribution
  • Standardization and accessibility


CARS Webinar:

To view or download a webinar that describes the development and implementation of CARS and includes a live demonstration of the software used, please visit this page.

For more information, access the full CARS synopsis or contact Erin Holmes, Director of Traffic Safety at

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