In horse racing, a horse is carted away from the track because it couldn't finish the race due to injury and is unable to walk on its own.
For humans:
To be physically carried from a bar or party by friends, bouncers, local authorities, and/or random people because of great intoxication and the inability to walk. Person is then placed into a vehicle and driven away.
To be taken away in a police van from a party, bar, or for general hell raising.
I had to be vanned off last night after drinking 20 shots and passing out on the hotel lobbyfloor.
The act of obtaining candy then being fucked in ass figuratively or literally, more often then not without consent from the victim being "White Vanned."