A blonde, a…

A blonde, a redhead, and a brunette are driving in a truck. The brunette and redhead are in the cab and the blonde is in the back. They accidentally drive off a bridge into water. The brunette and redhead get out and swim to the surface and wait for the blonde. After a few minutes the blonde surfaces and the other two ask, „What took so long?“ The blonde replies, „I couldn’t get the tailgate down.“