Don’t Take Airbags For Granted. They Don’t Always Work As Intended.

Michael GrossmanJanuary 31, 2018 4 minutes

Vehicle safety measures have improved by leaps and bounds since the first gas-powered carriages wobbled down dirt roads in the late 19th century.

One of the most recognizable developments in vehicle safety is the airbag. Since they were patented in 1951, airbags have gone into almost every vehicle that can carry one. Everyone's aware that of them, but I believe many people take their effectiveness for granted. We trust they'll keep us safe without thinking too hard about what they really do or how complicated they really are.

Hitting An Airbag Doesn't Feel Like a Pillow Fight.

One misconception among drivers is that an airbag, since it's basically a cushion, feels like one during a collision. While the idea is understandable, it's unfortunately not true. Impacting the bag is surely softer than hitting a dashboard or steering wheel, but its explosive inflation feels less like a pillow and more like a punch.

We've touched on this elsewhere, but to quickly recap: In a frontal collision the car stops moving but its occupants keep going forward. If nothing gets in their way, people in the front seats will strike the car's dashboard or steering wheel, which are not forgiving surfaces to hit at high speeds. In the worst cases, some may even eject through the car's windshield. To counteract this, airbags have to inflate using explosive force to create a large pliant surface area that catches the driver. They have just a few hundredths of a second to achieve that.

Anything moving fast enough when it collides with a human body--a bullet, a baseball, even a playing card--can hurt it. An airbag deployment is no different: Flying bodily into a balloon that forcefully explodes outward at you feels a bit like getting shot by a throw pillow fired from a bazooka. Broken noses, fractured ribs, and bruises galore are common in crashes where airbags serve their purpose. Grim though that sounds, I think it's safe to say that anyone injured in this manner still prefers it over the alternatives.

Modern airbag systems carry less risk of deployment-related injury than they used to. However, they're still more complex than they may seem. If anything goes just a little wrong during their deployment, they can be rendered useless--or even seriously dangerous.

They Also Aren't Failure-Proof.

Some may believe that airbags are simple; after all, how complicated can a balloon be? The answer is probably "not very" for, say, party clowns, but airbags require more than twisting them into a giraffe.

It doesn't take much to make an airbag useless
Airbag deployed on time vs. deploying 7/100ths of a second late.

Several things must happen with exact precision during the 30-40 milliseconds of an airbag deployment. Sensors must communicate the data of the collision (speed, direction) to one another. The Electronic Control Unit (ECU) must trigger the bag inflator's detonation. The bag itself has to fully inflate within a heartbeat's time. The process involves split-second interaction between electronics, electrical elements, and even explosive materials. Unfortunately errors still occur, like the one demonstrated below.

It's a little melodramatic but still true: The difference between life and death can sometimes be as short as .07 seconds. If an airbag sensor isn't calibrated correctly, triggers late, or is slow to relay a signal to the ECU, that blink of an eye can be enough time to split someone's metaphorical melon.

It's rare but possible for software bugs or shorts in the electrical relays to cause such delays. While electrical system damage can sometimes happen from standard wear and tear, faulty electronics are often a sign of manufacturer negligence. Going over a few bumps can't account for the vehicular equivalent of brain damage.

It's not just the electronic components either. Anyone who pays attention to the news will have seen dozens of headlines about Takata-brand airbags. Found in vehicles from several major manufacturers, these airbags are infamous for their dangerously-explosive propellant canisters. The National Highway Transportation Safety Administration (NHTSA) has gotten dozens of reports where the canisters, filled with ammonium nitrate (an unstable explosive found in some bombs), acted something like "claymore"-style land mines when triggered during a crash. Metal shards flew at the faces and torsos of unprepared drivers, causing serious--sometimes fatal--lacerations.

Don't Take Airbags for Granted.

Maybe it seems like I'm saying airbags do more harm than good. I don't mean to convey that impression: In the overwhelming majority of cases airbags deploy properly and save lives that otherwise might have been tragically cut short. I'm only suggesting that their technology isn't perfect.

If the scale of the Takata recall campaign teaches us anything, it's that we have to be responsible for our own safety instead of simply trusting that safety measures will rescue us from our mistakes.

Wear a seat belt, obey speed limits and traffic signs, keep your eyes on the road, and don't drive drunk. They're the basic rules we've known since Driver's Ed, but on average the U.S. sees about 16,000 crashes a day, suggesting that for many they didn't really sink in. Anyone interested in surviving their road trip might want to remember that a car's safety devices don't always work as intended, so the best thing any of us can do is avoid needing them in the first place.