In it, the system has been attached to a previous-generation Opel Insignia wagon (which we got in sedan form in North America as the Buick Regal). You can also see that there are a variety of extra sensors added to the edges of the bumpers and the side mirrors to help determine when to activate the airbag. As the car is driving, a flexible dummy car is thrown at it, and the airbag goes off a split-second before impact, allowing the airbag to take the brunt of the impact. In fact, ZF says the system can determine whether to inflate the airbag, which is itself between 5 and 8 times the size of a typical driver airbag, and then inflate it all within 150 milliseconds.
The idea for how this helps protect the passengers from a side impact is that the airbag works a bit like the crumple zone built into the front of a car. It adds more space for the impact to be absorbed and dissipated before reaching the occupants. According to ZF, the external airbag could reduce injury severity by 40% for passengers.
ZF's demonstration is impressive, and it proves that this technology is much closer to reality than we first thought. Of course, we suspect it will still be several years before we see it on any production cars. Companies will surely have to do extensive testing to make sure the airbag system activates within in the necessary time frame consistently and doesn't go off from false or misleading readings.