Maybe it works, maybe it doesn't.

Mine works. Pedestrian crossed the road in front of me one night in (slow moving) traffic and the car decided it was going to stop about three inches from her surprised legs.

On the other hand, someone on the Volvo forum says his has gone into frightened horsey mode every time it sees a dark space, so he can't ever get into a multistorey carpark without repeated attempts at under half a mile a week. Most embarrassing.

Volvo used to do a thing where they set up an inflatable thing and the dealer would let you try to hit it. I don't think they offer that any more, but they must have made a few sales that way, before, I suppose, the bubble burst.