The Volvo system is based on radar + camera and it's pretty obvious that that is the rear of a vehicle in front of the truck. It might not necessarily pick up every kind of stationary object.
Impressive but not really comparable. How would it perform at 75 mph?
It would do exactly what you would expect. It would increase the ABS pressure up to a limit that doesn't generate excessive G force to the passengers necks.
The impact would 100% still occur but at a much lower speed exponentially reducing the extent of injuries to all involved.
it wouldn't smash into the vehicle at full speed, like the Tesla