As bicycle uptake increases, so too do bicycle-car collisions. When a cyclist gets hit by a car head-on, there's a good chance their head will impact the windshield. And "Head injuries alone account for half of [cyclist fatalities]," writes Autoliv, a manufacturer of automotive safety systems.

These days we have pretty good bike helmets, and innovations like the automatically-deploying, airbag-inspired Hövding 3 head protector:

But Autoliv and POC, a manufacturer of protective equipment for cyclists and snow sport enthusiasts, looked at how much protection conventional bike helmets provide, and have concluded they need to do better in the higher-speed (20 km/h, or 12 mph) range of car-bicycle collisions. As an example, even the best helmet's not going to protect you from this:

To prevent an accident victim's head from impacting the windshield, several years ago Volvo looked at a concept incorporating a pop-up hood and external airbag:

Autonomous electric delivery vehicle company Nuro has added external airbags to their vehicles:

Autoliv, too, has looked at external airbags, including one for a scooter:

However, an external airbag on a car would only protect cyclists "lucky" enough to be hit by a vehicle outfitted with them. For cyclists who would like to better protect themselves, Autoliv and POC are collaborating on a bike helmet that itself contains an airbag. "Our ambition is to reduce severe head injuries at high speeds," they write.

"The airbag would act as the initial energy absorber while the underlying helmet would be the following energy absorber.

"After conducting a pre-study, conclusion from the Autoliv research team is that a cycle helmet with an integrated airbag can significantly improve protection and reduce the consequences of impacts to cyclists. The combination of both absorbing technologies enables a reduction of the peak linear head acceleration and significantly reduced head injury risk in impact tests. The pre-study also showed that the protection improvements could be reached without critically compromising the design, weight, or comfort of a helmet designed with integrated airbag technology.

"The pre-study showed that the addition of airbag technology on top of the helmet can significantly contribute to enhanced safety performance, especially in linear impacts. It is estimated that the risk for a bicyclist to sustain moderate to fatal head injuries is reduced from 80% to 30% in a 20 km/h (12 mph) impact."

At this point they're still in the research phase, and have not yet produced a prototype.