As a helmet designer, I have been asked many times why helmets don't have built-in airbags. I always kind of laughed it off, as even a first glance at the complexities involved would make it appear to be an impossibility.
But along comes Swedish Company, Hovding, which has attacked the problem and has an actual ready-for-retail airbag helmet in production.
How does it work? It is a circular collar covered in fabric that zips around your neck and rests on your shoulders. No helmet hair! They have analyzed the physics of a person falling in many crash scenarios and built an algorithm into internal sensors taking samples at "200 times per second" that, when they detect the rapid movement that indicates an upcoming crash, inflates a large fabric airbag hood within 1/10th of a second.
This airbag hood maintains full inflation pressure for a few seconds and then begins to depressurize.
This product surely represents a huge investment of time, money, and engineering skill which is represented in the price of 299 Euros or $338.
It's an impressive achievement and my hat, umm, helmet, is off to Hovding!