Semi truck engines have a (ussually) 5 min shut down, in other words if you leave it idle for more than 5 min, you will come back to a shut off engine . . . however, if you "bump" up the idle to say 1000 rpm with the cruise, then it will go till it runs out of fuel . . . they don't have a lot of oil presure at idle, and if your running the A/C or TV . . . puts more demand on the whole system . . . sure is rough vibs too, trying to sleep . . . 1000 rpm smooths it out!

Heated garages are nice too