First of all, FUCK all you guys being so mean!
Yes, drunk driving isn't cool. But it's not as simple as you think. People dismissing it and just saying "fuck you, you're an asshole etc" are full of shit. It's super easy to get a DUI! Sometimes you just have to get home, and you've had a couple glasses of wine, or have had a 40. You are great to drive, but that tail-light goes out and the cop sees a bottle of Merlot...
I won't lie, I have driven shitfaced many, many times back in the day during College. It's not a smart idea, but it definitely happens! The kids who die are the ones going fast, racing, driving wild, driving so drunk they can't see straight. Once again, I don't condone it at all, but stop hating so much!!
Personally, I am a better driver after a couple glasses of wine or after a 40, because I become severely more focused and into it, simply. Does this mean I should get a DUI? No. Be responsible, don't be dumb.
As far as the weed goes, you should be fine, they usually by law have to alert you if you are taking any drug tests for the first time etc.