Obviously Volvo is well aware of the potential for whiplash in situations where the driver and passengers are not expecting to be brought to a halt, so City Safety will only exert up to 50 per cent of maximum brake force. Of course this could mean that impact still occurs - depending on how close the other car is, and how fast the XC60 is travelling - but even if there is contact, damage will be significantly reduced due to the automatic braking.
I had the opportunity to try City Safety out for myself, and I have to say that I was very impressed. Jumping into an XC60 I drove it directly towards a stationary (albeit inflatable) vehicle at a speed of around 10mph, which is about what you'd be doing in slow moving traffic. As soon as I got close to the stationary car, the XC60 employed its brakes and brought us to a halt. Even when I upped the speed close to the 19mph limit of the system, the car still managed to call time before I hit anything.
The strange thing about testing a system like this is how unnatural it feels to drive towards an impending accident, consciously ensuring that I took no measures to avoid it. This wasn't lost on the my passenger from Volvo who advised me to look out of the side window, so I didn't notice the accident that was about to happen. How ironic, considering that's the exact excuse I was given by the guy who drove into the back of me!
The other area where City Safety will be a serious boon, is when you're queuing up at a roundabout. I've lost count of the amount of times I've been waiting behind someone at a roundabout and watching the flow of traffic - when a large gap in the traffic appears, I often assume that the car in front has moved off onto the roundabout, only to realise that they're still stationary. Luckily I've never driven into anyone at a roundabout, but I know plenty who have, and quite simply, those accidents wouldn't have happened with a system like this in place.
Those clever laser sensors aren't only used for City Safety either. Another system that's new on the XC60 is Pre-Prepared Restraints, which will get both the seatbelts and airbags ready for an impending impact, if the laser sensor detects one. So, seatbelts will tension and hold the passengers tighter against the seatbacks, thus ensuring that there is less chance of whiplash, while the specific airbags for the point of impact will be made ready before that impact occurs, again reducing the possibility of injury to the passengers.