When crashing makes you safer
Collision testing has forced improvements in vehicle structure,
Imagine you’re a young hotshot engineer. You’ve spent the past four years finite-element analyzing your company’s latest hot rod.
And then, in just 120 milliseconds — an eyeblink really — it’s gone, your pride and joy reduced to a crumpled, mutilated hunk of junk. The bumpers are crushed, the fenders accordioned and, if the hydraulic ram was feeling particularly spiteful that day, the wheels literally ripped off.
But here’s the thing: It’s exactly what you were hoping for!
Welcome to the wonderful world of crash testing, where “ultraviolence” is welcomed, pristine fenders and bumpers are destroyed daily and literally brand-new vehicles are sacrificed to the gods of collision.
A bit surreal is a deliberate automobile crash. For one thing, it happens in a huge, gleaming white warehouse, empty save for huge, reinforced concrete blocks (for the cars to smash into), a flotilla of ultraprecise $100,000 4K digital cameras that shoot at 500 frames a second (the better to capture the minutiae of the destruction) and an entire office of engineers with an almost childlike obsession for smashing things. It is also — as I found out at a recent Insurance Institute for Highway Safety (IIHS) small overlap test of Subaru’s 2017 Impreza — probably the only place you’ll ever see insurance agents absolutely giddy at the prospect of cars smucking into one another.
Childlike it may be, but the IIHS’s obsession is one of the major reasons the modern automobile is so much safer than its predecessors. To prove the point, the U.S. institute’s showroom is decorated with a 1959 Chevrolet Bel Air that was crashed head-on into a 2009 Malibu. One quick look at the relative destruction is proof positive that sheer mass is no guarantee of safety.
According to the institute’s statistics, “The chances of dying in a crash in a late-model vehicle have fallen by more than a third in three years,” at least in part because the IIHS’s tests have forced automakers to up the structural integrity of their automobiles. That means cars now absorb more energy in full frontal crashes, B-pillars (the vertical beam that forms the rear of the front door opening) don’t shear nearly as often in side impact crashes (which account for 24 per cent of all injuries and fatalities) and, in the latest of all IIHS’s myriad tests — the small overlap front crash — virtually all cars now pass, a huge upgrade compared with the 75 per cent that failed just two years ago.
They are not upgrades automakers have always accepted graciously. According to the IIHS, those initial failures in the overlap test — the hardest test to pass, by the way — caused quite a tizzy among automakers. They initially claimed that meeting the new standards would require up to 100 kilograms of extra steel to reinforce the cabin’s safety cage. And, says Becky Mueller, one of the senior research engineers at the institute, one of the solutions to upgrade existing cars was simply adding a bunch more metal to their superstructures.
Despite their initial griping, automakers have now managed to meet the latest standards without increasing weight.
More importantly, Mueller claims, the difficulty of passing the small overlap test — having just 25 per cent of the car’s front hit the barrier stresses the cabin’s framework far more than a full frontal test — forced automakers to use ingenuity as well as engineering might. Recent automobile designs — again, like the new Impreza that was just awarded the IIHS’s coveted Top Safety Pick+ rating — now design the front bumper so that it not only absorbs energy but also levers the car sideways, away from the barrier, reducing the impact.
In the end, however, there’s only so much to be gained by adding additional crash tests. Indeed, Russ Rader, IIHS’s director of communication, admits the institute’s barrage of tests have “picked all the low-hanging fruit” in protecting occupants in a crash.
Though it is looking at adding an oblique test — a small overlap test conducted at a 15-degree angle that stresses airbags and seat belts as much as the chassis — the IIHS’s focus of late has been in preventing accidents. Thus, as of 2014, to achieve the institute’s Top Safety Pick+, cars must have an army of electronic crash prevention systems. And for 2017, having determined there’s far more differentiation between automakers’ headlights than previously imagined, passing an illumination test is part of a Top Safety Pick+’s latest requirements. As to the future of crash testing, what seems to excite the IIHS’s engineers most is the prospect of having the pre- and post-accident electronic aids working together in an automobile.
As surprising as it may sound, the sensors that initiate airbag deployment currently don’t talk with the sensors that predict a crash is about to happen. In other words, airbags don’t inflate and seat belts don’t “pre-tension” until something has smacked into your front bumper:
In the future, however, Mueller predicts that the same automatic pre-collision system that predicts you’re about to get into an accident (and currently automatically applies the brake to try to prevent, or at least blunt, the impact) will alert the passenger-protection devices that a collision is unavoidable. The seat belts, for instance, would be pretensioned even before bumpers start kissing one another. Ditto the airbags, depending on the severity of the impact.