Loaded semi's really numb things.
I would certainly feel a car PIT'ing on my front and and dragging along for sure. But I do have a story about rear impacts driving a rig. One time I was working in the yard and I had to bring a truck around from the street to get the load taken off it, driver called out. We run day cab's with 42' flatbeds and a 3 wheeled pick machine hanging off the back. Truck was fully loaded with concrete form panels. I did the walkaround the truck. Clear behind me at the street corner, somebody parked in front of me.
I climbed in the cab and built up the air pressure, checked my mirrors. Proceeded to back up to clear the vehicle in front of me. Some dude runs and jumps up on my pass side door and starts pounding on it and yelling. I stop and get out to see WTF is going on. This punk snuck up behind the truck and parked right on my ass on the street corner. I had no idea and the 3rd wheel of the lift machine rolled right up the hood, through the windshield and half the roof into the front seats, then pushed the car back about 15'. I didn't feel a DAMN thing.
Thank god he was not in it. His co-workers were going ape shit on him for parking like that. I felt horrible too but what else was I to do to prevent it?
Same thing happened to a Fed Ex guy in our yard here, one of our customers in a big 'ol quad cab P/U pulled right up on his ass, he didn't see him and pushed that truck a good 25 feet. Brand new truck too, that guy with the P/U was beyond PISSED. I had to get in the middle of those 2 on that one, UGLY.
Moral of the story everyone, stay off trucks aszez and blind sides.