The model: Alcohol behind the wheel: the limit and the glass

One standard glass ≈ 12 ml of pure alcohol ≈ 0.2 to 0.3 promille (Book p.15) — whether it is beer (250 ml/5%), wine (100 ml/12%) or whisky (35 ml/35%). The body breaks that down at 0.1 to 0.2 promille per hour: one glass therefore already takes about 1.5 hours.