On November 28, 1996, a ghastly accident occurred in the US state of Idaho. A woman drove her car into the back of another car. Her one-year-old daughter, Alexandra, who was in the front passenger seat beside her, was decapitated. Her head was thrown “through the door window and into the parking lot,” news agency AP reported.
But it was not a high-speed crash. The two cars were inside a mall parking lot. The culprit was the passenger airbag in Alexandra’s mother’s car, which had expanded with its full force at 320 kmph.
By April 1997, airbags that were meant to save lives had killed 63 Americans, of whom 38 were children. Alexandra’s case was the goriest, but all were equally tragic. The American public was scared. Some 35 million cars and light trucks already had airbags, and from September 1, 1997, front airbags were going to be mandatory across America. There was a clamour for a switch to disable airbags.
Yet, here we are 25 years later when the number of airbags in a car is considered a measure of safety. People want airbags, and transport minister Nitin Gadkari is pushing carmakers to oblige. So, how did the once-feared airbag become a must-have? Let’s rewind 50 years.
Cushion for the careless
We now see airbags as the primary safety device in a car, but 50 years ago that was not the case. The seat belt was, and perhaps still is, the single most important safety device in your car. Although seat belts in the 1960s and 1970s were basic lap belts (there was no strap across the shoulder), they did save lives.
As Ford’s executive vice-president Fred Secrest told a US Senate Committee hearing on August 1, 1973: belts alone were more effective than airbags “primarily because belts keep people from being thrown out of the car…. The chances of an occupant being killed in an accident are four times greater if the occupant is ejected from the car.”
A front airbag only protected the occupant from injuries that occurred due to impact on the steering wheel and the windshield, but a three-point belt (shoulder+lap) was just as good. Secrest said: “The airbag was intended to be a superior crash pad, to reduce the severity of the second collision impact of a lapbelted occupant in a frontal collision.”
So, why were automobile companies spending millions of dollars developing airbags, and why was the Senate committee so eager to see them installed in cars?
The problem was, although cars came fitted with belts people didn’t use them. In 1972, just 20% of American car users wore seat belts even though 38,000 car occupants had been killed and 3.5 million injured in crashes that year. Wearing a seat belt was not compulsory, and imposing a countrywide seat belt rule was politically difficult.
That’s why lawmakers were keen to have a “passive restraint system” that would protect careless car occupants in a crash. Insurance firm Allstate’s director of automotive engineering, Jack Martens, told the committee, “The airbag is a device that works in spite of occupant apathy.”
The insurance industry said 66% of accidents were front-end collisions, and 89% of accident deaths occurred in the front seats. So, the focus was on providing front airbags. In fact, a rule to make airbags mandatory in all cars sold in the US after August 15, 1975 was announced but it was stalled by a court over doubts regarding the design of crash dummies used to test airbags.
Lifesaver from the start
Nonetheless, carmakers had extensively tested airbags by 1973. About 2,000 GM and Ford cars had covered 55 million kilometres between them, and there had been 12 crashes in which their airbags had deployed. The results were largely excellent. In one case, a Mercury (Ford) driver had driven into the back of a parked car at 109kmph without a seat belt. He had slid forward in his seat and fractured his knee but was unharmed otherwise.
A minor girl had driven her car into a railway sign. The impact had broken the engine mountings but the girl and her friend had walked away from the crash unharmed.
It won’t be allowed today but some of the early airbag testing was done using baboons in place of dummies. And to ensure that the gas that inflated the airbag was not toxic, monkeys were exposed to it in a sealed space for 30 minutes.
Though the airbags performed well, they were very much a work in progress. There were doubts about their reliability in very cold places like Alaska, and concerns about permanent hearing loss from their explosive deployment. But all the testers who had been in an accident said they had never heard the bag deploy as the crash itself had been louder.
So, how did the ‘benign’ airbags of the early 1970s turn into somewhat dangerous and unpredictable devices by the 1990s?
Powerful to a fault
Well, this was a result of trying to protect occupants who did not wear belts. US guidelines at the time required that airbags should be able to protect an “average adult male not wearing a seat belt”. But the average US male was heavy. The current figure is about 200 pounds or 90kg.
To stop a heavy man from crashing into the steering wheel during an accident, the airbag had to deploy with great force. At the 1973 Senate committee hearing Ronald H Haas from GM’s Oldsmobile division had said that in a 50kmph crash, the time available to deploy was 0.04 seconds, or one twenty-fifth of a second.
The force was simply too much for lighter people, such as children and old women. While airbags were saving lives, they were known to sometimes cause arm fractures in drivers. If the car wasn’t moving fast, and the occupant’s body did not have enough forward momentum, the airbag “punched” their head backward with too much force. This could cause injuries to the face and the head, and also make the neck snap backwards. That’s how little Alexandra Greer had been decapitated.
The good news was that by the mid-1990s seat belt use had risen across the US, so experts advised depowering airbags by 20-35%. Another suggestion was to improve the way airbags were folded and tucked into the steering and the dashboard. The unravelling folds could be used to direct an airbag’s force away from the occupant.
Advanced sensors that could detect the speed of the vehicle, the size and weight of an occupant, and whether they were belted or not, also helped in making airbags safer with time.
A boon despite flaws
The airbag is still not perfect, and unlike a seat belt you can’t find out how good it is till you have an accident. And even if engineers develop the perfect airbag, the possibility of manufacturing defects can’t be wished away.
The Takata airbag recall that started in 2016 affects 67 million airbags in 42 million vehicles and is still not complete. These airbags sometimes malfunction in hot and humid conditions, especially when they are old. They contain an ammonium-nitrate-based propellant that can ignite spontaneously, sending metal shards from the airbag flying around the cabin.
At last count, faulty Takata airbags had killed at least 27 people worldwide since 2002, according to Consumer Reports. But on the other hand, airbags have saved at least 50,000 lives since 1987 in the US alone. So, on balance, the airbag is a device that you would rather have in your car.
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