Our Volvo V40 saved our butt once on the highway. Late at night, cars piling up all of a sudden in front of us. The car slammed the brakes and stopped us a few meters away from the car in front :-)
I also have a V40 and have also had an experience exactly like that on a motorway - bright red lights flashed at the bottom of the windscreen along to a warning sound and the autonomous braking kicked in and stopped me from hitting the car in front. Excellent system.