Hill start assist. It functions by allowing you to stop on an upward angle, take foot off the brake and transfer it to gas, all without the truck moving. This allows you to more carefully maneuver without having both feet on the gas and brake at the same time.
So I tried it on a 40-45 degree incline yesterday. It starts the hill start tone (which lets you know it will hold for 5 seconds) aand the whole time the vehicle is moving backwards... very slowly, but its moving backaward at like half a mile per hour. If I had really needed it to work that could have cost me position as I could have dropped back off a precarious rock or something... so why does the system suck at holding you in place?
On the flip side the DAC works really well. It sometimes does not come on for a foot or two but once its on it does not fail to keep speed at 3mph or less on steep drops or even on flat ground after ther drop. Made several 45 degree decents with no brakes or gas... pretty cool.