Who You Calling "Marginal"?

Results from the IIHS’ latest small SUV roof crush test are making the rounds of the autoblogosphere, and as usual the spoonfed information is being dutifully regurgitated in the name of consumer safety. What goes largely unreported is the fact that the IIHS is gleefully moving the roof crush goalposts, a unilateral decision with little benefit to consumers and a host of unanticipated consequences. Current roof crush standards mandate that vehicle roofs must support 1.5 times the weight of the vehicle, and have been in effect since 1973. The IIHS has been campaigning for years to increase government roof strength standards, and an uprated standard of 2.5 strength-to-weight ratio is currently being considered by the NHTSA. So where does the 2.5 standard rate with the IIHS? “Marginal” is the score that the IIHS gives to vehicles meeting this not-yet approved standard. Huh?

Only four of the 12 small utes tested scored a “good” on the IIHS scale: Subaru’s Forester, VW’s Tiguan, Honda’s Element and Jeep’s Patriot. And what did they have to do to climb that mountain? Support four times the vehicle’s weight while buckling less than 5 inches. That’s two and two-thirds times tougher than the current federal minimum and just under twice as tough as the proposed federal minimum.

So why the roof-crush zeal from the IIHS? More than 10,000 people a year are killed in rollovers, say the insurance industry-funded boffins. And, “our research shows that a strength-to-weight ratio of 4 reflects an estimated 50 percent reduction in the risk of serious and fatal injury in single-vehicle rollover crashes compared with the current federal standard of 1.5.” Yes, in a rollover crash. Therein lies the rub.

Improved roof crush standards improve the chances of surviving a rollover, but as our Bob Elton pointed out way back when, forcing up roof crush standards actually increases the likelihood of rollovers occuring in the first place. More roof reinforcement raises a vehicle’s center of gravity, making it far more likely to roll. And what’s the point of making vehicles safer in the case of a rollover if they become more likely to roll in the process? Preventative medicine (stability control, driver training) and smarter rollover safety equipment (curtain airbags) are the answer, not the IIHS’s blind adherence to roof crush standards.

And the consequences of the IIHS’s roof strength fixation are not limited to the increased chances of rollovers. By more than doubling federal standards in its testing, the IIHS is pushing OEMs into a corner where safety and efficiency begin to trade off. As automakers scramble to meet uprated (and far more nationally significant) CAFE standards, the IIHS’s desire to see more roof and pillar steel stand in their way.

And despite these major tradeoffs to the IIHS’s agenda, the Institutes’ own research shows that roof strength is improving anyway. “Manufacturers have made structural improvements to earn better front and side ratings,” says the IIHS report. And though they admit that these overall safety improvements have improved roof crush performance, the IIHS’ insistence on the 4 times vehicle weight standard means only four vehicles receive a “good” rating. Not “outstanding” for having performed at over two times the federal standard, just “good.”