NP don't drink & drive

[Otto]

Alcohol impairs driving more than marijuana
New Scientist

A single glass of wine will impair your driving more than smoking a joint.
And under certain test conditions, the complex way alcohol and cannabis
combine to affect driving behaviour suggests that someone who has taken both
may drive less recklessly than a person who is simply drunk.
http://www.newscientist.com/news/news.jsp?id=ns99992063
http://www.spiegel.de/wissenschaft/mensch/0,1518,188169,00.html