All things being equal, I’d rather get hit by a car with an external airbag.

Just don’t let me ever read “though the driver was texting behind the wheel,because the pedestrian airbag deployed, police did not file charges.”

They are doing this to meet Euro NCAP standards that state that by 2015 automakers’ products make collisions
survivable when they occur between a pedestrian and a car moving at
40kph (24.9 mph). The airbag is probably required because of the length of the hood. You probably won’t see this in the United States where no such requirement exists.

Though I appreciate the skepticism expressed, there do seem to be few additional benefits:  
(a) It would eliminate the hit and run for this type of crash.
(b) The design of the front-end necessary for this to work prevents the pedestrian from being knocked down and under the vehicle — we need to see that universally adopted, and this would only help.
(c) Whereas another commenter noted that the airbag would protect the windshield, in practice it would cost more to replace the airbags than to replace a damaged windshield. 

I visited the Volvo engineering headquarters in Goteborg, Sweden when attending the int’l conference on driver distraction and inattention, and Volvo has made a pledge to improve the design of their cars so that they don’t kill anyone by 2020. Its a remarkable commitment, and the head engineer of their pedestrian safety team seemed to have a good head on his shoulders.  

I think on Laughing Squid someone commented that it will make it difficult to drive after hitting someone as your windscreen would be covered by the bag. This would make hit and run quite difficult!

But also I wonder if all the benefits will be cancelled out by risk compensation — and I also wonder if the people who get this before it is required are the more careful drivers in the first place…

Bottom line is that it’s another “solution” that does not change the horrible and insane urban private automobile paradigm

(note: previous comment should have been “a few additional benefits”)

@Green_Idea_Factory:disqus 
If “law of physics” question refers to @f730b5d1874944680f9356185ac7f304:disqus (b) below, it relates to the height of the nose of the vehicle and the design of the hood. There are now pedestrian crash test requirements that have been introduced in Europe and Japan, but are not pertinent in the US. These are a good thing.

The concept of “risk compensation” was clearly demonstrated among drivers when cars were outfitted with airbags, but I don’t think the same is true for pedestrian collisions. I had this suspicion when I first saw the publicity for the Volvo active pedestrian safety system in 2008. But, in demonstrations, it surprised me — I think that in practice, it likely makes the drivers more observant of pedestrians and pulls them out of their “invisible” status.  

After that experience, I now think that having active pedestrian safety systems is on par with having alert systems for drowsy drivers.  We know that there is a high incidence of drowsy driving and falling asleep at the wheel, and those systems don’t seem to make it more likely that there are drowsy drivers on the road.

Mixed feelings here. On the one hand, anything which will mitigate the effects of an auto colliding with a pedestrian is a good thing. On the other, it’s a sad commentary that such collisions happen often enough to warrant such a device as this.

I first read about this on Gizmodo, and I immediately dismissed it as a way to get drivers off the hook when they get into accidents, and said that it’s better to improve driver behavior.

However, I do agree that it would be beneficial in the event of a collision (should work for car-cyclist collisions as well).

Pre-crash braking and steering are the usual reasons they move too close to the dashboard. This turns a minor 10 mph crash into a 140 mph head impact with the air bag.