Answer:
Disclaimer: It is never safe to drink and drive, answer provided for entertainment purposes only. Depends on your jurisdiction and weight but a male in excess of 175 lbs can drink 3 beers in an hour (and no more than 1 beer every hour thereafter) and still be legal in Ontario.
The amount of beer one can drink and still be legal to drive is when someone's blood alcohol reaches .08. Outside of this number there is no EXACT number of beers someone can drink because some people can constantly drink before feeling any effects and others get tipsy after only one beer.