By on June 6, 2019

There was a time when the only thing cushioning your head from a direct impact with the steering wheel in the event of a crash was the skin it was wrapped in. Since then, airbags have proliferated, breeding inside millions of cars to a point where they now explode down from the headliner.

Considering automotive safety pretty much only moves in one direction, this was bound to happen. There may come a day when airbags are no longer limited to the interior of cars.

ZF Group, best known for its transmissions, is currently testing a “pre-crash external side airbag system” that it considers to be the world’s first. Having debuted a prototype in 2016, ZF is now conducting live demonstrations where an inflatable barrier bursts forth from the rocker panel to provide additional cushioning for side impacts. 

Three years ago, ZF said the system could reduce impact forces by 30 percent. Now, it claims a 40 percent reduction in occupant injury severity, as well. Apparently, designing and refining on-demand crumple zones was the easy bit. ZF says the biggest challenge to the project involved developing a system that could work with existing sensors to accurate predict when an unavoidable collision will occur.

Since most consumers wouldn’t appreciate external airbag deployments every time they pull out into traffic, the system has to have exceptionally good reflexes. ZF says the entire rig has approximately 150 milliseconds — roughly the same time it takes a person to blink — to make the decision to deploy the airbag and then do so.

From ZF:

The vehicle’s sensors first have to identify a potential impact quickly and accurately. This is possible with connected cameras, radar and lidar. Algorithms within the system software decide whether or not a collision is unavoidable and the deployment of the airbag is both possible and beneficial. If these decisions are all affirmative, the system ignites the inflators to fill the airbag. The airbag, which has a capacity of between 280 and 400 liters (five to eight times the volume of a driver airbag) depending on the vehicle, then expands upwards from the side sill to form an additional crumple zone in the door area between the A and C pillars.


The company recently revealed test footage of the system where it absolutely demolished the car it was stacked against. Unfortunately, that vehicle appears to have been made out of air and rubber tubing. But the impact forces endured are undeniable. The test-bed Opel clearly begins to rotate from the hit, with nary a hint of deformation.

“We highlighted that this safety system has the potential to significantly reduce occupant injury severity in cases of side impact collisions,” said Uwe Class, head of the ZF Advanced Engineering team’s Safe Mobility Systems department. “Our deep understanding of the entire ’see. think. act.’ process enables us to conceptualize and realize integrated vehicle safety solutions such as the new pre-crash safety system.”

As for claims as to whether or not this is a world first, we have to bring up Volvo’s pedestrian airbag system. It’s fallen out of favor with the brand of late, but it technically trumps ZF’s rig for being the world’s first external inflator — forcing the supplier to include the “side” caveat and making them technically correct. Regardless, ZF’s system could become the first airbag to be utilized between cars if it’s ever adopted for use in production vehicles.

[Image: ZF Friedrichshafen]

Get the latest TTAC e-Newsletter!

17 Comments on “Inside Out: ZF Tests External Side Airbag System...”

  • avatar
    SCE to AUX

    Pretty clever idea, but as you say, the tough part will be the control algorithm.

    I can foresee a scenario where it deploys to protect against an errant shopping cart, only to launch said shopping car into an adjacent pedestrian or another vehicle.

    • 0 avatar

      Sounds like a youtube opportunity.

    • 0 avatar

      If it’s fast enough for an approaching car then it will have absolutely no trouble deploying way ahead of any shopping cart impact. Unless you shoot the shopping cart at it at over 60mph…

      Look at Dainese D-Air motorcycle rider airbag systems: they are purely based on rider-attached motion sensors and algorithms, and they deploy dependably and fast enough to protect a rider falling from their bike in a low-side.

    • 0 avatar

      If they can tune it to launch the cart at the irresponsible person who let it roll, sign me up.

  • avatar

    I know that the incoming vehicle is a mockup but all the airbag did was directs its movement vertically. What about when that car is a kid on a bike?

    • 0 avatar

      No, it dissipates the impact peak loads. Just like, say, an Airbag…

      When it’s a kid on a bike either the algorithm will determine that the approach speed is so small that deployment isn’t necessary, or then it deploys. In that case the kid on a bike, instead of hitting metal directly, hits the airbag.

    • 0 avatar

      BTW that test was clearly done just to test the deployment of the airbag, not to test the behaviour in an impact with a real car.

  • avatar

    What kicks the target car sideways is the sled the balloon cars is on as it goes under the right rear wheel.

  • avatar

    I do not like it. I would prefer to have permanently deployed protection shield in my car. It will also make armored cars obsolete.

  • avatar

    They think I can’t tell its an Opel

  • avatar

    For North American market they better put it at window sill level. Full size pickup is the best selling vehicle here by a huge margin.

    • 0 avatar

      They really need to do something about lifted trucks.

      If you “need” the lift to go off-road, then limit the allowable number of miles driven per year before it has to be returned to stock height, OR require Mansfield bars in front, rear, and the sides.

  • avatar
    Art Vandelay

    Good. Put something based on this up front for pedestrian safety and bring back my sweet 90’s low hoodlines

    • 0 avatar

      Sweet low 90s hoodline saved me when I was hit by a car.

      Sent me onto the hood, rather than under the vehicle. Given that I flew off the hood, that brief ride tells me that I was in a safer place. Hell, where the bumper hit my leg was one of the few places that didn’t hurt.

  • avatar

    Better get to work on Securefoam©™ instead.

  • avatar

    What are those body colored nobules on the test victim’s bumper? Cameras of some sort, sensors?

    I like this concept, of ot can be perfected. It would probably work best in tandem with collision mitigation braking system where you’ll get a shouty STOP light, a shouty klaxon, and then a “we told you to do a thing; Jeeves apply the brakes full force” and hope for the best application of a suite of the things.

Read all comments

Back to TopLeave a Reply

You must be logged in to post a comment.

Recent Comments

  • mcs: I’ve always been a fan of the 2121 Niva. The bada$zed 4×4 version. They made 650,000 of them....
  • Michael S6: My wife got a new green GrandPrix GT 2005 and it was a royal POS. This was a brand new model and Pontiac...
  • Superdessucke: Yup. If you got into an accident and that big plastic piece came off, you’d have that cheap...
  • Inside Looking Out: I had Lada 2108 and once in a while to cut standing still traffic on the road I took shortcuts...
  • Crosley: I remember getting one of these as a rental, and just being awe struck how cheap the interior felt even in...

New Car Research

Get a Free Dealer Quote

Who We Are

  • Adam Tonge
  • Bozi Tatarevic
  • Corey Lewis
  • Mark Baruth
  • Ronnie Schreiber