Any gun in my truck that I have decided stays in the truck for any length of time, be it a handgun or AR, is considered a back up gun. Its nothing I plan in getting to quickly. Its an extra tool should i find myself in a situation where things are escalating (broken down car in the middle of nowhere, stuck at the cabin, etc) and need something more.
I keep the gun cased with the magazine removed and spares at the ready.