The effects of alcohol on eye movement behaviour during driving

One dose (weighted and sex-dependent treatment) will be taken orally (by mouth) under supervised administration at each session [i.e. active treatment: weighted dose of alcohol (vodka) with orange juice to reach 0.05% Blood Alcohol Concentration (BAC); weighted dose of alcohol-free vodka with orange juice as the placebo treatment (control)]. The order of dosing will be randomised with a one-week washout period between testing sessions. The active treatment is a weighted and sex-specific dose of vodka and orange juice drink to achieve 0.05%BAC. This will be achieved using an adjustable calculation based on the Watson method of dosing per estimated total body water for men and women (derived from height and weight) rather than only body weight, as per 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) 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). Participants are given 10 minutes to finish the drink, which is followed by a 10-minute absorption period Prior to dosing at each testing visit (each at V1 & V2), participants will provide one saliva sample to screen for evidence of recent use of drugs [amphetamine/d-methamphetamine, 3,4- methylenedioxymethamphetamine (MDMA), cocaine, cannabis (del ta-9-tetrahydrocannabinol) and opiates] using the Securetec DrugWipe 6s device. This screening assessment requires an absorbent pad to be placed over the tongue for approximately 20 seconds. 1ml of saliva will be taken per sample, therefore approximately 3ml in total over each of the three experimental sessions. A sample volume of less than 10 micro litres is sufficient for analysis. The device is wiped on the tongue, when the colour has changed from pink to yellow there is the required amount of saliva to obtain the results. The DRUID mobile app (Impairment Science, Inc.) will be used to assess the psychomotor and cognitive effect of the intervention. Four tasks will be used in this study to measure balance, reaction time, psychomotor vigilance, hand–eye coordination, attention to motion stimuli, and time estimation. Participants will be assessed at approximately 15 and 95 minutes post-dosing. The SRAVI app (Liopa) will be used to will be used to examine how alcohol consumption affects speech and to develop tools that can potentially identify different states of intoxication based on speech and lip movement patterns. Participants will complete the speech task before each driving test at 25 and 105 minutes post-dosing. A purpose-built mobile app will be used to collect data from participants during speech tasks during the speech task. Prior to the driving task, participants will communicate with the software via a dedicated Android phone mounted in a car (when the car is stationary only). Participants will be instructed to position their faces with the phone's camera and start the video by following the directions on the screen. The app will display a series of short phrases for the participants to read out loud and record video of lip movements as well as audio. Driving performance with simultaneous eye monitoring will be evaluated during on-road driving. Each participant will complete two seperate visits, corresponding to placebo and 0.05%BAC. Within each visit, participants will undergo four 15-minute driving tests to evaluate performance at baseline (pre-dosing), ascending (20 minutes post-dosing), peak (60 minutes post-dosing) and descending BAC levels (100 minutes post-dosing). These assessments will be conducted in an instrumented vehicle manufactured by Build Your Dreams (BYD Auto Co., Ltd., Shenzhen, China), equipped with automatic transmission and dual controls to allow for instructor intervention. Each 15-minute drive will follow the same pre-determined route around METEC Driver Training's closed-circuit course in Bayswater North. This highly controlled environment is closed to regular traffic and designed to include a combination of 40 and 60 km/h speed zones, along with a variety of road conditions and challenges to appropriately evaluate driving abilities and responsiveness. The hard-surfaced track is intended to mimic typical Australian road conditions, with gradual to sharp turns and a mix of single and dual lanes, each with a width of approximately 3 metres. It also features mid-line and side markings, as well as standard Australian road signage. The overall anticipated duration of each visit is 4 hours