.5
promille as they say down here. Or 0.05%.
Which is roughly .22 mg of ethanol per liter of blood.
Calculators indicate that 4 standard units (meaning two glasses of 8%ABV beer) for a man of 80kg would lead to .63 promille, an hour after consumption.
An hour later, you'd be good to go.
Of course, calculator don't realise most people don't sit down to quaff two Chimay Bleus and then wait for two hours for the effect to wear off
Beer and travel always brings the conundrum of transport and logistics. If you have a friend who doesn't like beer enough to drink but who likes you enough to drive you, then you're all set