Car crash Car crash

2020.04.20 Hyundai MOBIS 분량7min

World’s First Roof Airbag Is Born

Roof Airbag is a device to restrain occupants to protect them in case of a car crash and reduce the degree of injury. This technology will be much more frequently used in the era of autonomous driving.

Since the 1980s, when cars first started to become mass-produced, airbags became a necessary element to keep passengers alive. When sensors detect a collision, chemicals in an airbag creates gas to fill it up, making it a balloon-like cushion. Carmakers kept developing it to create the second-generation 'Depowered' airbag, which makes it 30 percent softer to decrease airbag injuries. Then it evolved into the Dual Stage airbag and the Advanced airbag that can adjust the intensity of the airbag deployment depending on the weight of the passenger.

Rollover: Seat Belts Won’t Help

Damaged vehicles

Insurance Institute for Highway Safety(IIHS) in the United States tests cars to evaluate the intensity of the roof-Photo: IIHS (

And these are still not enough to prevent crash injuries. When a car rolls over, the passengers inside would get injured from every direction. In this case, front and side airbags won't do all the work here. Passengers can also get injured by being thrown out of the sunroof during an accident. Of the 13,700 subversive accidents that occurred in North America for 15 years from 2000, 2,400 cases were reported where passengers fled the vehicle, with 10 percent of them thrown out of the sunroof.

Passengers ejected in rollover crash

17 percent of the passengers were ejected from their vehicle in rollover crashes

According to data on Hyundai Mobis' roof airbag released by the U.S. National Highway Traffic Safety Administration(NHTSA), experiments under various conditions showed that it has been effective in preventing passengers from leaving through the sunroof. Roof airbags spread in 0.08 seconds in the event of a rollover accident and prevent passengers from bouncing off the sunroof, reducing head and neck injuries. Senior Researcher Min Byung-Ho of Hyundai Mobis now tells us about the details.

Roof Airbag

Roof airbag is a state-of-the-art feature to save people’s lives

Q. Where did you first get the idea from?

Usually, automakers develop most of their safety features based on the guidelines of the National Highway Traffic Safety Administration(NHTSA), Insurance Institute for Highway Safety(IIHS), or The European New Car Assessment Programme(Euro NCAP). The Roof Airbag, on the other hand, is an evolutionary technology that no one has ever thought of. After conducting a safety assessment on roof airbags, Hyundai Mobis figured out a roof airbag can protect passengers by covering the entire ceiling of a car when a car is overturned.

No Roof Airbag and Roof Aribag

Q. Is the roof airbag still effective while wearing a seat belt?

Regular seat belts are very effective in a frontal crash. However, it cannot stop your body from moving upwards in a rollover crash. The roof airbag will not only prevent the passenger from being thrown out of the car but also protect them from serious multiple injuries.

The parts of a roof airbag

Q. How does a roof airbag work?

Mounted around the sunroof, the sensor triggers the airbag when it detects a collision or rollover. The airbag is coated with silicone to maintain its inflated shape up to 6 seconds. Stainless wires increase the deployment speed, helping the roof airbag safeguard the passengers better and it has been effective in preventing sunroof passengers from leaving. Roof airbags spread in 0.08 seconds in the event of a rollover accident and prevent passengers from bouncing off the sunroof, reducing injuries.

The sensors make sure the airbags successfully deployed. This system consists of the sensing unit that collects information from sensors in real-time, such as the intensity and type of collision, seatbelt use, and occupant size. Then it determines the optimal restraint devices, including seatbelt pretensioners, curtain airbags, and roof airbags.

Q. Which type of vehicles will mostly benefit from the roof airbag?

The roof airbag will be more effective in SUVs and sedans with a panoramic sunroof than other kinds of vehicles. And autonomous cars in the future will also benefit from the roof airbag since the passengers will be sitting in all different directions. These autonomous cars will feature a spacious cabin, which highly likely to increase the chance that the passengers get thrown out of the car in a rollover. The roof airbag, then, will become a necessary element.

Autonomous concepts feature a glass body

Most autonomous concepts feature a glass body

After the NHTSA sending their opinion to Hyundai Mobis that they want to evaluate the ability of the roof airbag, they confirmed the effectiveness of the product. The result would be meaningful to Hyundai Mobis because the NHTSA is a trustworthy institution. The National Highway Traffic Safety Administration is responsible for keeping people safe on America's roadways. Through enforcing vehicle performance standards and partnerships with state and local governments, NHTSA reduces deaths, injuries, and economic losses from motor vehicle crashes.

Experiments conducted last year under various conditions showed that it indeed is effective in keeping passengers from thrown out of a car, and the roof airbag is durable and environmentally friendly enough as well. Big sized SUVs and premium models will have the roof airbag first, and the airbag will continue to evolve.