i think this is a great idea - a genuingly smart way to promote the message
as they say, it's not overly obtrusive, and as well as delivering an important message, it also increases the realism of the game. too often the billboards in these racing games are so similar and artificial - but here will be ones that look as much like they are real billboards along the streets outside.
the only slight problem is that most people playing these games will be at home, with no need to drive.
and who drinks alcohol while playing computer racing games anyway? it slows your reaction time so much you'll never get a decent lap time