Publication

This pre‑study examines the technological landscape, practical experience, and regulatory requirements related to in‑vehicle detection of alcohol‑ and drug‑impaired driving, focusing on alcohol and cannabis.

Current detection approaches fall into five categories: physiology‑based systems (breath, sweat, biosignals), tissue spectroscopy, camera‑based driver monitoring, vehicle kinematics, and hybrid systems. No single modality today offers sufficient specificity to reliably detect alcohol or drug impairment during real driving. Physiological sensing best reflects substance presence, but integration hurdles remain; behavioural sensing (oculomotor patterns, posture, vehicle control) reveals impairment but lack specificity. Hybrid systems that combine presence‑based and behaviour‑based indicators has the greatest potential.

Practical experience from prior intoxication studies carried out by the project partners highlighted key operational requirements. Reliable experiments depend on high staffing density, strict safety protocols, disciplined event logging, and carefully tuned alcohol dosing procedures. Recruitment is challenging and requires screening for health, medications, sleep patterns, and substance use history. Breath‑based ground truth measures require rigorous protocols, and evidential‑grade analysers are recommended in future studies. Closed‑track environments remain necessary for safety but may not fully reflect real‑world driving. Simulator extensions can complement realism. Across partners, there was strong alignment on experimental design for future alcohol studies, with growing interest in shifting focus toward cannabis impairment.

Conducting cannabis experiments in Sweden requires a full clinical‑trial application through the EU CTIS system, reviewed by both the Medical Products Agency and the Ethical Review Authority. A medically responsible investigator and a compliant drug manufacturer must be secured before submission. Additional requirements include medical screening, on‑site medical staff, blood and specimen handling procedures, and detailed documentation of the cannabis product. In addition, a separate government permit is needed because driving under drug influence is illegal even on closed tracks. Recruitment will be particularly challenging due to the illicit status of cannabis in Sweden, and the method of drug administration (vaporised, smoked, capsules, edibles) must be selected to balance safety, impairment dynamics, and sensor detectability.

Taken together, the project show that:

• Robust detection of alcohol and drugs will likely require multi‑modal sensing and careful experimental design.
• SAFER partners already share substantial know‑how for alcohol studies, but cannabis research introduces additional legal, medical, and logistical complexities.
• A future multi‑partner cannabis study is feasible but will require early coordination with medical investigators, compliant manufacturers, and regulators, alongside realistic timelines for approvals and recruitment.