What is the maximum blood alcohol level allowed for driving a passenger car, as a general rule?

Correct answer: 0.5 grams per liter of blood.

For a passenger car, the general limit is 0.5 g/l in blood or 0.25 mg/l in exhaled air. It applies to adult drivers who have held a license for two years or more. The limit for novice drivers is 0.3 g/l, and for underage drivers, 0.0. No driver has a limit of 0.8 g/l.

Reglamento General de Circulación — Real Decreto 1428/2003