In-Vehicle Real-Time Cannabis Influenced Driving Detection (REVELIO)

Randomised, Controlled, Interventional Single-center Study for the Design and Evaluation of an In-vehicle Real-time System for Detecting Cannabis-impaired Driving (CID)

The goal of this clinical trial is to evaluate whether in-vehicle sensor data can be used to detect cannabis-impaired driving in healthy adult recreational cannabis users.

The study aims to assess whether changes in vehicle, driver, and physiological sensor data can distinguish sober driving from cannabis-impaired driving, and how driving performance changes from baseline to approximately 1 to 6 hours after controlled cannabis consumption.

Researchers will compare driving behavior and in-vehicle sensor data from participants who receive controlled cannabis administration with data from a randomized reference group without cannabis exposure, to determine whether cannabis-related impairment driving can be identified on the basis of machine learning.

Participants will complete screening and baseline assessments and drive an instrumented vehicle on a closed test track under sober conditions. Participants assigned to the experimental arm will receive controlled cannabis administration, while participants in the reference arm will receive no intervention. All participants will perform repeated standardized driving sessions over several hours and complete traffic-medical, traffic-psychological, and in-vehicle pre-driving tests. Biological samples and in-vehicle sensor data will be collected throughout the study.

Study Overview

• Status: Recruiting
• Conditions: Driving Under the Influence; Cannabis-impaired Driving
• Intervention / Treatment: Drug: Cannabis (THC)

• Study Type: Interventional
• Enrollment (Estimated): 45
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Wolfgang Weinmann, Prof. Dr.; Phone Number: +41 31 684 01 61; Email: wolfgang.weinmann@irm.unibe.ch
• Study Contact Backup: Name: Michal Bechny, Dr.; Phone Number: +41 76 221 62 56; Email: mbechny@ethz.ch

Study Locations

• Switzerland
  • Bern, Switzerland, 3008
    • Recruiting
    • Institute for Forensic Medicine, Forensic Chemistry and Toxicology University of Bern
    • Contact: Wolfgang Weinmann, Prof. Dr.; Phone Number: +41 31 684 01 61; Email: wolfgang.weinmann@irm.unibe.ch
    • Contact: Michal Bechny, Dr.; Phone Number: +41 76 221 62 56; Email: mbechny@ethz.ch

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Informed consent as documented by signature
• Recreational cannabis-consumption (more than once per month)
• In possession of a definite Swiss or European Union (EU) driving license
• At least 21 years old
• Active, regular driving a car in the last 6 months
• Must be in good health condition
• No special equipment needed when driving (special seats, levers, etc.)
• Fluent in (Swiss) German and no speech impairment

Exclusion Criteria:

• Health concerns where cannabis consumption is contra-indicated (such as: high blood pressure, psychiatric problems (e.g. psychosis, depression, attention-deficit conditions, etc.)
• Cannabis-abstinence or excessive consumption, , assessed using the Cannabis Use Disorders Identification Test-Revised (CUDIT-R)
• For women: pregnancy or breastfeeding or if intention to become pregnant during study period (time between telephone screening and study day (visit 2)
• Alcohol misuse or excessive alcohol consumption habits/risky drinking behaviour, assessed using the Alcohol Use Disorders Identification Test (AUDIT) and/or phosphatidylethanol (PEth) in capillary blood > 200 ng/mL at first visit
• If breath alcohol test is positive at Visit 1 or Visit 2 (study day)
• Consumption of drugs of abuse (others than cannabis) within 4 weeks before the study
• Consumption of medications / pharmaceutical drugs which interfere with driving ability
• Inability to follow the procedures of the study, e.g., due to language

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Diagnostic
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Controlled Cannabis Administration; Participants assigned to this arm receive a single, controlled inhalative administration of cannabis by smoking a THC-containing joint with a target dose of approximately 0.67 mg THC per kg body weight. Participants complete standardized driving sessions in an instrumented vehicle on a closed test track under sober baseline conditions and repeatedly after cannabis administration (approximately 1-6 hours post-dose). All driving sessions are conducted with a certified driving instructor seated in the front passenger seat with access to dual pedals, allowing immediate intervention if required. Multimodal in-vehicle sensor data, physiological signals, driving performance measures, and biological samples are collected throughout the study.	Drug: Cannabis (THC); Participants assigned to the experimental arm receive a single, controlled inhalative administration of cannabis by smoking a THC-containing joint (target dose 0.67 mg THC per kg body weight; cannabis flowers with 15-18% THC).
No Intervention: Reference (No Cannabis); Participants assigned to this reference arm receive no cannabis administration. They complete the same screening procedures, standardized driving sessions, assessments, and data collection as the experimental group under sober conditions, following the same schedule and time points. All driving sessions are conducted with a certified driving instructor seated in the front passenger seat with access to dual pedals, ensuring identical safety conditions. This arm serves as a non-impaired reference for comparison of driving behavior and in-vehicle sensor data.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Diagnostic accuracy (AUROC) of a multimodal machine-learning model for detection of cannabis-impaired driving	Area under the receiver operating characteristic curve (AUROC) of a single machine-learning classifier that integrates multimodal in-vehicle data (including vehicle controller area network [CAN] data, driver monitoring camera [DMC] features, and physiological signals). All modalities are combined into one predictive model, and performance is reported as one aggregated AUROC value distinguishing non-impaired (sober) driving from cannabis-impaired driving.	Baseline (sober driving) and up to 6 hours after cannabis administration in the experimental arm, with matched time points in the reference arm.

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Diagnostic accuracy (AUROC) using CAN data	AUROC for detecting cannabis-impaired driving using vehicle controller area network (CAN) data only.	Baseline (sober driving) and approximately 1-2, 3-4, and 5-6 hours after cannabis administration in the experimental arm, with matched time points in the reference arm.
Diagnostic accuracy (AUROC) using DMC data	AUROC for detecting cannabis-impaired driving using driver monitoring camera (DMC) data only.	Baseline (sober driving) and approximately 1-2, 3-4, and 5-6 hours after cannabis administration in the experimental arm, with matched time points in the reference arm.
Diagnostic accuracy (AUROC) of a physiology-based machine-learning model for detection of cannabis-impaired driving	AUROC of a single machine-learning classifier trained and evaluated using aggregated physiological features only, derived from signals including heart rate, heart-rate variability, oxygen saturation, electrodermal activity, skin temperature, and respiration-related measures. All physiological signals are combined into one predictive model, and performance is reported as a single AUROC value distinguishing non-impaired (sober) driving from cannabis-impaired driving.	Baseline (sober driving) and approximately 1-2, 3-4, and 5-6 hours after cannabis administration in the experimental arm, with matched time points in the reference arm.
Change in driving behavior derived from vehicle CAN data	Change in driving behavior between sober driving and post-cannabis driving, derived from vehicle controller area network (CAN) signals, including steering, braking, acceleration, and velocity-related measures.	Baseline (sober driving) and approximately 1-2, 3-4, and 5-6 hours after cannabis administration in the experimental arm, with matched time points in the reference arm.
Change in driver gaze behavior derived from DMC data	Change in gaze behavior between sober and post-cannabis driving, derived from driver monitoring camera (DMC) data, including gaze direction and gaze dynamics during driving.	Baseline (sober driving) and approximately 1-2, 3-4, and 5-6 hours after cannabis administration in the experimental arm, with matched time points in the reference arm.
Change in head movement behavior derived from DMC data	Change in head movement behavior between sober and post-cannabis driving, derived from driver monitoring camera (DMC) data.	Baseline (sober driving) and approximately 1-2, 3-4, and 5-6 hours after cannabis administration in the experimental arm, with matched time points in the reference arm.
Driving instructor assessment of driving performance	Assessment of driving performance conducted by a certified driving instructor, quantified as the number of safety interventions required during each standardized driving session.	Baseline (sober driving) and approximately 1-2, 3-4, and 5-6 hours after cannabis administration in the experimental arm, with matched time points in the reference arm.
Diagnostic accuracy (AUROC) of an in-vehicle pre-driving readiness test for detection of cannabis-impaired driving	AUROC of a machine-learning (ML) classification model implementing a study-specific in-vehicle pre-driving readiness test. The test produces an ML-derived readiness score, computed from features derived from the pre-driving test (e.g., attention-related, reaction-time-related, and psychomotor-related features), and is used to classify driving sessions as sober versus post-cannabis.	Baseline (sober driving) and approximately 1-2, 3-4, and 5-6 hours after cannabis administration in the experimental arm, with matched time points in the reference arm.
Performance in the standardized Psytest assessment	Performance in the standardized Psytest assessment (mobility version of the Test of Attentional Performance), administered under sober conditions and after cannabis consumption. Test performance is summarized using a standardized test score reflecting overall attentional and psychomotor performance relevant for driving.	Baseline (sober driving) and approximately 1-2, 3-4, and 5-6 hours after cannabis administration in the experimental arm, with matched time points in the reference arm.
Self-reported subjective effects	Self-reported subjective effects assessed using study questionnaires, including subjective feeling of "high" and degree of sleepiness. Responses are recorded using a Likert scale ranging from 0 to 10, where 0 indicates "not at all" and 10 indicates "extremely." Higher scores indicate a worse outcome, reflecting stronger subjective drug effects and greater sleepiness.	Baseline (sober driving) and approximately 1-2, 3-4, and 5-6 hours after cannabis administration in the experimental arm, with matched time points in the reference arm.
Cannabinoid biomarker concentrations in biological samples	Concentrations of Δ9-tetrahydrocannabinol (THC) measured in capillary blood, oral fluid, and breath samples.	Baseline in all participants, and approximately 1-2, 3-4, and 5-6 hours after cannabis administration in the experimental arm.
Incidence of adverse events	Incidence of adverse events and serious adverse events recorded during all study visits.	From the first study procedure (i.e. baseline assessment) to the end of the main study day (i.e. driving assessment) expected to be on average up to 6 hours.
Change in heart rate during driving	Change in heart rate measured during driving between sober conditions and post-cannabis conditions.	Baseline (sober driving) and approximately 1-2, 3-4, and 5-6 hours after cannabis administration in the experimental arm, with matched time points in the reference arm.
Change in oxygen saturation during driving	Change in oxygen saturation measured during driving between sober conditions and post-cannabis conditions.	Baseline (sober driving) and approximately 1-2, 3-4, and 5-6 hours after cannabis administration in the experimental arm, with matched time points in the reference arm.
Change in electrodermal activity during driving	Change in electrodermal activity measured during driving between sober conditions and post-cannabis conditions.	Baseline (sober driving) and approximately 1-2, 3-4, and 5-6 hours after cannabis administration in the experimental arm, with matched time points in the reference arm.
Change in skin temperature during driving	Change in skin temperature measured during driving between sober conditions and post-cannabis conditions.	Baseline (sober driving) and approximately 1-2, 3-4, and 5-6 hours after cannabis administration in the experimental arm, with matched time points in the reference arm.
Change in respiration during driving	Change in respiration measured during driving between sober conditions and post-cannabis conditions.	Baseline (sober driving) and approximately 1-2, 3-4, and 5-6 hours after cannabis administration in the experimental arm, with matched time points in the reference arm.

Collaborators and Investigators

• Sponsor: University of Bern
• Collaborators: ETH Zurich; University of St.Gallen
• Investigators: Principal Investigator: Wolfgang Weinmann, Prof. Dr., Institute for Forensic Medicine, Forensic Chemistry and Toxicology University of Bern

Study record dates

Study Major Dates

• Study Start (Actual): January 5, 2026
• Primary Completion (Estimated): June 19, 2026
• Study Completion (Estimated): June 19, 2026

Study Registration Dates

• First Submitted: January 22, 2026
• First Submitted That Met QC Criteria: February 3, 2026
• First Posted (Actual): February 10, 2026

Study Record Updates

• Last Update Posted (Actual): February 10, 2026
• Last Update Submitted That Met QC Criteria: February 3, 2026
• Last Verified: February 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Behavior; Criminal Behavior; Dangerous Behavior; Driving Under the Influence; Organic Chemicals; Hydrocarbons; Terpenes; Cannabinoids; Dronabinol; nabiximols
• Other Study ID Numbers: 2025-01590

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No