Alcohol, Drugs, and Impaired Driving
How Impairment Works
Alcohol and drugs degrade the skills driving demands: judgment, reaction time, coordination, and vision. Impairment begins with the first drink - there is no safe threshold. Alcohol is absorbed faster on an empty stomach and metabolized slowly; coffee, cold showers, and food do not sober a person up, they only mask symptoms. Time is the only thing that clears alcohol.
Blood alcohol concentration (BAC) is the legal measure. For drivers 21 and over, the common legal limit is 0.08%. For commercial drivers it is typically 0.04%, and for drivers under 21, zero tolerance laws apply - any measurable alcohol can trigger a violation. Refusing a chemical test usually triggers license consequences under implied consent laws, regardless of whether you were impaired.
Drugs - including prescription and over-the-counter medications - can impair driving. Read labels; many cause drowsiness. Combining alcohol with any drug multiplies impairment. Marijuana impairs judgment and reaction time and is illegal to drive under in most jurisdictions.
Traps to Watch
Questions often test the myth-busting facts: coffee does not sober you, and a cold shower does not either. Another trap is the "one drink" assumption - impairment starts before the legal limit. Watch for implied-consent questions: refusing a test has consequences even if you are under the limit. Also be alert to questions about prescription drugs, which count as impairment even when legally prescribed.
Rule of Thumb
If you have consumed anything that could impair you, do not drive - designate a sober driver, call a ride, or wait.