An On-track Trial to Assess Driving from Alcohol

THE ALC-TRACK trial is a closed-circuit track study designed to assess the effects of alcohol on driving performance, focusing on cognitive and behavioural outcomes among healthy participants. Driving performance will be assessed individually, at the same testing sites as medical cannabis study (CAN-TRACK - ACTRN12624001118594) at the Australian Automotive Research Centre (AARC) and Metropolitan Traffic Education Centre (METEC). This randomised, double-blind, placebo-controlled trial will assess real-world driving performance in 24 healthy participants. Participants will undergo repeated driving assessments on four separate days. Specifically, participants will undergo 1 alcohol and 1 placebo session at each site (AARC and METEC) in a randomised crossover design. The study schedule is detailed below- (0) Screening session: Eligibility criteria assessed by a registered research nurse at Swinburne University of Technology. This screening session will last approximately 1-hour. (1) Alcohol/placebo session at AARC. A practice drive will be completed 15 minutes prior to baseline. Baseline driving performance will be assessed approximately 20-hours prior to administration of alcohol/placebo. This session will last approximately 2 hours and will occur on Day 1 (i.e., Monday). (2) Alcohol/placebo session at AARC. Assessed continuously during each driving session at baseline (pre-dose), at 0.5-hour post-dose, and 1.5-hour post-dose. This session will last approximately 5 hours and will occur on Day 2 (i.e., Tuesday). (3) Alcohol/placebo session at METEC. Assessed continuously during each driving session at baseline (pre-dose), at 0.5-hour post-dose, and 1.5-hour post-dose. This session will last approximately 5 hours and will occur on Day 3 (i.e., Wednesday). (4) Alcohol/placebo session at METEC. Assessed continuously during each driving session at baseline (pre-dose), at 0.5-hour post-dose, and 1.5-hour post-dose. This session will last approximately 5 hours and will occur on Day 4 (i.e., Thursday). Driving performance tasks will include telemetry data collection and driving instructor ratings, and will last approximately 25 minutes each. The entire study duration for each participant is approximately two weeks (inclusive of screening a week prior). Alcohol sufficient to produce a BAC of 0.05% or a placebo (alcohol-free vodka and orange juice) will be administered orally, under the supervision of the researchers. The intervention will be delivered face-to-face, individually, at the same testing sites as Arm 1 (medical cannabis). The dosage will be precisely calculated using a weighted, sex-specific formula that adjusts for estimated total body water, as determined by the Watson method. This approach, which factors in height and weight rather than body weight alone, ensures an accurate dose tailored to each participant to achieve the target BAC of 0.05%, as detailed in the equation below: 1. Total Body Weight (TBW) men (Litres, L) = 2.2447 - (0.09516 x age) + (0.1074 x height) + (0.03362 x weight) 2. TBW women (L) = 2.097 - (0.1069 x height) + (0.2466 x weight) E.g., for an average 70 kg male person to achieve 0.05%BAC, this will require dosing of ~111g of 40% alcohol, or 4 standard drinks (30mL shots) with 334g mixer orange juice (total drink 445g). Adherence to the intervention will be closely monitored, with researchers supervising the administration of alcohol/placebo during the study sessions. Participants will be given a 15-minute window to consume the allocated alcohol/placebo drink.