Not only would this be great for all the possible mods that use alot of civilan vehicles, would be great in every aspect.
I sooo badly want to be able to whip my rifle out the window and let off some rounds whilst cruising at comfortable speeds in my random vehicle.
Perhaps the "turn out/turn inn" function could be utilized in such a way that you would pop out the side window of any given vehicle(assuming it has a window) or from the back of an ATV and be able to fire your personal weapon freely.