Assessing how cannabis affects driving impairment

Cannabis Consumption and Driving Impairment Assessment on a Closed Course

Phase 2 Interventional California Department of Motor Vehicles · NCT06059677

This study is testing how smoking cannabis affects people's driving skills by having volunteers take driving tests after using cannabis, a placebo, or nothing at all.

Quick facts

PhasePhase 2
Study typeInterventional
Enrollment300 (estimated)
Ages21 Years to 55 Years
SexAll
SponsorCalifornia Department of Motor Vehicles Government
Locations1 site (Sacramento, California)
Trial IDNCT06059677 on ClinicalTrials.gov

What this trial studies

This study involves approximately 300 volunteers who will smoke either active cannabis, a placebo, or no substance at all. Participants will then undergo a driving test while being observed by California Highway Patrol officers to determine their level of impairment. The study aims to validate existing behavioral assessments used by law enforcement for detecting cannabis-induced driving impairment against a comprehensive driver evaluation. This research is conducted in a controlled environment to better understand the effects of cannabis on driving abilities.

Who should consider this trial

Good fit: Ideal candidates are individuals with a valid California driver's license who have used cannabis in the past six months and can comply with study requirements.

Not a fit: Patients with physical or psychological conditions exacerbated by cannabis use or those with a history of substance use disorders may not benefit from this study.

Why it matters

Potential benefit: If successful, this study could improve the accuracy of impairment assessments for cannabis use, enhancing road safety.

How similar studies have performed: While studies on alcohol impairment have been extensively validated, this approach to assessing cannabis impairment is relatively novel and has not been widely tested.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion Criteria:

* Possessing a valid California driver's license
* Cannabis use in the past six months
* Willing and able to abstain from alcohol, cannabis, and other recreational drugs for 24 hours prior to scheduled participation
* Willing and able to avoid driving and operating heavy machinery for at least four hours after participation
* Residence within approximately 15 miles of the study site
* Possessing the capacity to provide informed consent

Exclusion Criteria:

* Completion of a roadside sobriety test during the previous 12 months
* Physical or psychological conditions that can be exacerbated by cannabis use, or for which cannabis use is contraindicated
* Potential presence of Cannabis Use Disorder as assessed by a modified version of the Cannabis Use Disorder Identification Test
* Potential presence of Substance Use Disorder as assessed by a modified version of the Drug Abuse Screening Test
* Pregnancy or breastfeeding reported
* Unwillingness to be transported by taxi
* Having been convicted of Driving Under the Influence (DUI) within five years prior to scheduled participation
* Parole or probation status
* One or more felony convictions on record involving aggressive or dangerous criminal activity
* Any of the following at the time of the experimental session: breath alcohol content of .01% or greater; positive pregnancy test; cannabis consumption considered unsafe following medical checkup by the study nurse; or driving test behavior considered hazardous by the driving examiner

Where this trial is running

Sacramento, California

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
Conditions Cannabis SmokingDriving Impaired
Last reviewed 2026-06-09 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.