Alcohol, Drugs, and Driver Fitness
What this domain tests
This domain covers the legal alcohol limit, how alcohol and drugs affect driving, and the fitness issues that quietly cause crashes: fatigue, medication, poor eyesight, heat and illness. Questions often ask you to judge whether a driver is still over the limit, or to identify the only safe response.
Core facts
- Cambodia's legal maximum for drivers is 0.05% blood alcohol concentration (50 mg per 100 ml).
- Alcohol is a depressant: it slows reactions, narrows attention, worsens distance judgement and increases confidence, a dangerous combination.
- The body clears roughly 0.015% BAC per hour. Coffee, cold showers, food and sleep do not speed this up.
- Illegal drugs and driving under their influence are prohibited; some prescription medicines cause drowsiness, so read the label and ask a pharmacist.
- Fatigue is impairment: after roughly 17-19 hours awake, performance resembles being over the drink limit.
- Declare eyesight, hearing or seizure conditions that affect safe control, and wear corrective lenses if your licence requires them.
Worked example
A driver stops drinking at 1 a.m. with an estimated BAC of 0.18% and drives at 7 a.m. Six hours at 0.015% per hour clears about 0.09%, leaving roughly 0.09%, still nearly double the 0.05% limit and clearly impaired. The reasoning is elimination rate, not how the driver feels; a big breakfast and a shower change nothing.
Traps
- Assuming a few hours of sleep restores sobriety.
- Treating strong coffee as a cure rather than a stimulant that masks drowsiness.
- Ignoring a medicine label that warns against driving.