Or when someone does this?

http://www.youtube.com/watch?v=rBEmInSdsx4

Check this out a shoulder airbag for bike racers...

http://www.youtube.com/watch?v=mo9Vlt5tGwY

And: Skier saved from deadly avalanche by airbag backpack -- Engadget

I think the airbag/helmet for bikers could really save lives on a regular basis.

I agree...I think we have only scratched the surface here, I'd like to see these air bags built into the pants as well....

Yeah, and there will be special under the clothes strategic airbags for those club nights.

Firstly, why do you say it is not for mountain biking or BMX? Here in the UK cycling on the roads is certainly far more dangerous than mountain biking or BMXing. The destructive loads are much greater (juggernaut or bus vs. tree or rock) and the timing is much shorter (certainly on mountain bikes you usually see the impact coming; on road bikes you don't).

Secondly, traditional cycle helmets are very poor, and do not give good overall protection to the head or neck. I don't know how designs, standards and testing are regulated, but as far as I can see the only good thing to be said about traditional helmets is that they are slightly better than no helmet at all. My impression is that this design is certainly no worse, and possibly much better.

I can agree that road riding can certainly be more dangerous than off road. My statement that this product may not be suited for off road is the likelihood of an unintentional deployment due to riding on very rough terrain.

"certainly on mountain bikes you usually see the impact coming"

Not really, that oak jumped right in front of me at the last second. Fortunately, I cushioned the impact with my face, so all was well.

Good point, and noting the regular shaking-up of the competitors at the recent Olympic mountain biking, the helmets would have been popping open all over the place.

If we fix airbags to the external surface of all vehicles including aircrafts lot of lives and equipments could be solved.

.......could be saved not solved.

Aviation airbags

Not sure what external airbags would achieve. Airbags aren't cushions they're energy dissipation devices.

They could be designed and constructed using tough material inflatable automatically upon crash.

External airbags have been discussed as a way of reducing injuries when vehicles hit pedestrians. The idea is that sensors detect the immanent impact and deploy to cushion the blow.

Not sure how many lives would be saved fitting then to aircraft though.

There's a lot going on in this space at the moment. Airbags for bikers, ones that form a 'shell' around a child's car seat, neck protectors for vehicle drivers..... Interesting times.

An airbag can't replace the protection offered by the rigid shell of a helmet.

I see it more as a complimentary thing. Airbags in cars do not replace seatbelts they supplement them. Hence the SRS badge on the dashboard

Here's an airbag helmet, best of both worlds.

How about an airbag suit? You'd have that whole Michelin Man thing going on.

or this......