I wrecked a car once in my younger days. Fell asleep a couple of blocks from my place, but had no idea how exhausted I was - hadn't even been drinking and it was a quick cross-town drive. Nobody got hurt including myself, which was absolutely incredible, since the car got murdered and I even knocked down a utility pole. Miracle witnessed. Lesson learned.
Now I just stack the odds in my favor, especially after a long show where I've spent a whole lotta energy and still need to drive. I might have one beer early in the evening at a gig, but I'll usually make sure that the cold ones are waiting for me in the fridge at home.
I pulled several 9+ hour hauls between home and the Norfolk, VA area back in my navy years. Coffee and chewing tobacco were helpful at first, but that chew is simply nasty stuff. I found that I could stay amped up really well just by keeping a good supply of chewing gum handy. I'm way more frosty behind the wheel when I'm jawing away on that stuff.
I pretty much don't drink more than a beer at gigs. Sometimes for long night-time car trips I'll have a coke or an iced coffee on the road.

