Tech Talk: Why GM’s centre airbag is 2013’s best new technology
It’s unlikely that many of the automotive journalists on the judging panel for AJAC’s Best New Technology award would have predicted the ultimate winner, before final presentations by the manufacturers.
But when the envelope was opened on stage at the Canadian International AutoShow as part of the Automobile Journalists Association of Canada’s Car of the Year Awards, General Motors’ Front Centre Airbag had scored a clear victory. For good reason.
Now in its 16th year, AJAC’s Best New Technology Award is adjudicated by a panel of 12 AJAC journalists with specific technical backgrounds and qualifications, including me and fellow Wheels contributor Jim Kenzie.
After first trimming an initial list of 23 entries to a short list of 10 finalists, we were sequestered for a day while the manufacturers individually presented their cases for their short-listed technologies. Each had 5-10 minutes to make their pitch, then another 5-10 minutes to answer questions from the panelists.
We then completed and submitted our own secret ballots, for compilation by the international accounting firm KPMG.
Going into that day, I hadn’t considered the centre airbag system to be a favourite. After all, automakers have been adding airbags for decades now.
Plus, as long-time panel member Marc Lachapelle pointed out before announcing the winner, the quality and depth of the entries this year was the best ever, with multiple potential winners.
So what gave GM’s centre airbag the edge?
Only the individual voters know for sure, but in my mind it was not just the technical achievement itself but the fact that it addresses a safety issue that has been pretty much overlooked until now.
Scott Thomas, a senior staff engineer working on advanced restraint systems at GM has spent the past five years rectifying that situation.
According to data Thomas has mined from the U.S. Fatal Analysis Reporting System (FARS), 39 per cent of all fatalities to belted occupants in non-rollover crashes are the result of side-impact collisions — second only to frontal crashes, which account for 54 per cent.
The adoption of side-impact and head-curtain airbags has gone a long way to addressing that situation in crashes where the occupant is sitting on the same side of the vehicle that is hit (near-side impacts).
But, surprisingly to many of us, occupants on the opposite side of the vehicle from the impact (far-side impact), account for fully 29 per cent of all non-rollover side-impact fatalities (11 per cent of total).
Those are the occupants the front centre airbag is designed to protect primarily, although there are benefits to near-side occupants as well.
The airbag deploys from the right side of the driver’s seatback and internal tethers force it to wrap slightly around the driver, like a big catcher’s mitt.
The inflatable part of the airbag is figure-eight shaped, thicker at the top than the bottom, to provide increased head protection. Unlike a frontal airbag, which deflates immediately, it stays inflated for up to five seconds.
There are multiple injury modes common to side-impact crashes, Thomas explained, with thorax, head and arm trauma accounting for the vast majority of injuries, in almost equal proportion.
Body-to-body and/or head-to-head impact between the two front-seat occupants are among the most dangerous injury modes. They aren’t the only dangers, however.
In fact, 58 per cent of front occupant deaths in far-side impacts occur to a single driver occupant.
While today’s three-point shoulder belts are highly effective in restraining occupants in frontal crashes, they’re not so helpful in preventing lateral displacement, particularly toward the centre of the vehicle.
It’s not uncommon, as Thomas illustrated by real-world example, for the driver’s head or body to make contact with the opposite-side door in the absence of another occupant.
The GM Centre Front Airbag is designed to help reduce injury in all those cases.
Among the test data Thomas presented, sequential photos of a 32 km/h side-impact crash test into a pole showed the head of a biometric dummy in the driver’s seat moving beyond the midpoint of the passenger-seat backrest.
With the centre airbag inflated, the head was restrained not far beyond the centreline of the vehicle.
Similarly, in the same test with two dummies on-board, the airbag creates a cushion between them, preventing contact with each other.
The GM Front Centre Airbag is currently available on the company’s Buick Enclave, Chevrolet Traverse and GMC Acadia mid-size utility vehicles. It will be offered in additional models in the near future.