Recognizing Intoxication and Signs of Impairment
What impairment looks like
Look at speech (slurred, loud, repetitive), eyes (bloodshot, glassy, drooping), motor control (stumbling, spilling, fumbling money or a phone), judgment (aggressive, overly familiar, crying, undressing), and memory (repeating an order, forgetting a tab). Count drinks and note the time. Impairment is a trend across the visit, not a single snapshot.
The numbers
A U.S. standard drink contains about 0.6 fl oz of pure alcohol: 12 oz of 5% beer, 5 oz of 12% wine, or 1.5 oz of 40% spirits. The body clears roughly 0.015 BAC per hour, and nothing speeds that up - coffee, food, cold air, and walking around do not sober anyone. Delaware's DUI threshold is 0.08 for drivers 21 and over and 0.02 for drivers under 21 under zero-tolerance rules. Delaware's implied-consent law means refusing a chemical test carries license consequences of its own.
Worked example
A 180-lb man drinks four 12-oz beers at 5% between 8:00 and 10:00 p.m. Pure alcohol equals 4 x 0.6 = 2.4 oz. A Widmark estimate gives (2.4 x 5.14 / 180) minus (0.015 x 2) = 0.069 minus 0.030 = about 0.039. He is under the legal driving limit, but at 0.039 he may already be slurring and unsteady, especially if he is tired, on medication, or a light drinker. Your decision rests on observed behavior and drink count, not on a number that says 'legal.' The estimate is also a population average; body composition, food, and genetics move individual BAC.
Traps that cost marks
- Assuming tolerance equals sobriety. A heavy drinker can be at 0.15 and still walk a straight line.
- Letting a guest sober up on coffee and then drive.
- Counting 'drinks' while ignoring doubles, 9% craft beer, or oversized wine pours.
- Missing polysubstance use - cannabis, stimulants, or prescription medication - that changes behavior.
- Watching the drinker and ignoring the friend who says 'I'm the driver' while drinking.