Bicycles

Airbag helmets outperform conventional helmets in drop tests

Airbag helmets, like the Hövding, are designed to stay out of the way until they're needed, and may prove to be safer than conventional foam helmets
Airbag helmets, like the Hövding, are designed to stay out of the way until they're needed, and may prove to be safer than conventional foam helmets
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In drop tests, the the Hövding airbag helmet design was found to be up to six times better at reducing impact, as measured by linear acceleration, compared to conventional helmets
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In drop tests, the the Hövding airbag helmet design was found to be up to six times better at reducing impact, as measured by linear acceleration, compared to conventional helmets
Airbag helmets, like the Hövding, are designed to stay out of the way until they're needed, and may prove to be safer than conventional foam helmets
2/2
Airbag helmets, like the Hövding, are designed to stay out of the way until they're needed, and may prove to be safer than conventional foam helmets

Bicycle helmets may be increasingly packed with technology like LED turn signals, radio communication and blind spot detection to help prevent accidents, but once a rider is involved in one, the method of protecting the head from hitting the ground hasn't really changed much. Now a team at Stanford has put self-inflating airbag helmets through their paces, with drop tests showing that they may be up to six times better at cushioning impact than traditional foam helmets.

The airbag helmet in question is the Hövding, which, most of the time, is a collar waiting to be a helmet. It is designed to sit around a rider's neck like a puffy scarf, but when it detects a collision, it quickly inflates and wraps around the head in time to soften the blow. The Hövding is already available in parts of Europe, but hasn't yet made it to the US.

CE-standard tests suggest that this design perform well, but to see how it might improve on conventional helmets, Stanford bioengineer David Camarillo and his team put the airbag helmet through standard drop tests. The pre-inflated helmet was placed on a dummy head fitted with accelerometers, and dropped onto a metal platform from different heights ranging between 0.8 and 2 m (2.6 and 6.6 ft). The linear acceleration of the impact was measured as the dummy struck the ground with either the top or side of the head.

"We conducted drop tests, which are typical federal tests to assess bicycle helmets, and we found that airbag helmets, with the right initial pressure, can reduce head accelerations five to six times compared to a traditional bicycle helmet," said Mehmet Kurt, one of the study's authors.

In drop tests, the the Hövding airbag helmet design was found to be up to six times better at reducing impact, as measured by linear acceleration, compared to conventional helmets
In drop tests, the the Hövding airbag helmet design was found to be up to six times better at reducing impact, as measured by linear acceleration, compared to conventional helmets

Linear acceleration is a good measure of the risk of a skull fracture and other head injuries from a given impact, but it doesn't necessarily say anything about the wearer's chances of sustaining a concussion. Studying this was a particularly personal goal of Camarillo's, having suffered two cycling-induced concussions himself.

"Foam bike helmets can and have been proven to reduce the likelihood of skull fracture and other, more severe brain injury," Camarillo says. "But, I think many falsely believe that a bike helmet is there to protect against a concussion. That's not true."

The reason for that is that scientists still don't fully understand specifically what about a blow to the head causes a concussion. Currently, the leading theory is that a twisting motion, more so than a linear one, is responsible, and although protection against this kind of injury wasn't directly measured in the team's tests, they believes the airbag helmets would probably still perform better than their foam counterparts thanks to their larger size and softer surface.

"There are many theories as to why concussion happens, but the predominant one is that, as your head rotates very quickly, the soft tissue within your brain contorts and, essentially, what you get is a stretching of the axons, which are the wiring of the brain," says Camarillo.

Next up, the team wants to measure how much the airbag helmets defend against these unwanted brain contortions, and determine how that can be improved, with an ultimate goal of improving the safety laws around helmet testing to cover concussion protection. Studying how the helmets fare from higher falls and what levels of inflation are necessary are other subjects the team has slated for further research.

In the lab, the helmets were pre-inflated to optimum pressure, but in the real-world, they're designed to inflate automatically when a collision is detected. This process may not guarantee that the airbag will inflate to the safest pressure, in which case the wearer's noggin may be worse off than if it was wrapped in a regular helmet. However, future versions may be able to predict how bad an impact is going to be and inflate itself to the optimum pressure.

The research was published in the Annals of Biomedical Engineering.

The team discusses the project and demonstrates the drops in the video below.

Source: Stanford University

Bike helmet showdown: Stanford researchers test new airbag tech

6 comments
Deres
I have some reluctance with those inflating designs : - they should be tested with non planar obstacle that could puncture them - they should be tested for abrasion tests also that could also puncture them - they should be tested with multiple impacts as a puncture could limit their ability against a second shock - there is the possibility of unexpected inflation to take into accounts in the risks - finally, i am sure the detection mechnism worlks well with an out-of-the-production model, but will it work so finely after several years of use oudoor ?
KaiserPingo
Still doesnt protect against damage directly to the face, or hitting an insect with 110 km/h. What when you scrape along the asfalt, for several meters ? But I can see a combination of the hard shell, foam lined fullface and this airbag-system.
Grunchy
I have a cousin who looks quite a bit like the model, though not so skinny. Anyway - I'm skeptical of this "at the last second, it swings into place" type of technology. I wear a seat belt; my Miata has a fixed-in-place roll bar; I have a foam bike helmet with hard shell. I don't rely on an air bag to pop out of my steering wheel; for a rollover bar to spring into place behind the seats; or for a bike helmet to jump out of my neck collar. Take a close look at the model, and notice the ear rings she is wearing (because fashionable females are liable to wear dangly, jangly ear rings). Could you imagine what an air bag helmet would do to her ears if it exploded up and over her head? Or the pony tail coming off her head. Anyway, whatever. I carry an actual spare tire in my trunk, not a fix-a-flat aerosol can.
Nik
People have been killed by the penetration of handlebars or brake levers on the bike, so a protection against sharp objects is essential, eg, corners of curb stones, not just from striking a flat surface. Of course the best protection, is not to fall off in the first place.
Timelord
I like the idea of the Hövding, just not the cost and not the current design. It really doesn't need to look like a cowl, which has the disadvantage of not protecting the forehead. Make it expand into a cylindrical tube, open at the top and about 6-8" taller than the head. If you crash, you don't need unobstructed vision immediately. Much more important to protect the face and forehead. Forget about how it looks after deployment. Make form follow function.
Jason Pase
For some reason this helmet reminds me of that scene from The Silence Of The Lambs where the dude threw semen at Jodie Foster 😖 ewwww
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