I don't know if you heard about [URL=http://news.bbc.co.uk/2/hi/technology/6410061.stm]this story[/URL]
A study from [URL=http://www.bsm.co.uk/]British School of Motoring[/URL] says that "27% of motorists aged under 24 admitted more risk-taking on the road after a gaming session".
At this point, I don't know more than what BBC says... and BBC doesn't say a lot : I don't know which games were tested, nor how the study was conducted (and indeed, it's much more a poll than a "real" study). And I found nothing on BSM's website (but I didn't search much, actually).