How Safe Are Those Seats?

Your children might well ride in the in your SUV or minivan every day. But just how safe are those seats and their head restraints? Well, according to the Insurance Institute for Highway Safety (IIHS), there's about a two-to-one chance that the seats your children ride in are not what they should be. The designs of seats and head restraints in 21 current SUV, pickup, and minivan models are rated good for protecting people in rear impacts, but those in 54 other models are rated marginal or poor. Another 12 are rated acceptable. The takeaway is this: The latest evaluations of occupant protection in rear-end collisions found that the seat/head restraints in more than half of light truck and minivan models fall short of state-of-the-art protection from neck injury or whiplash.

Among the best performers are the seat/head restraint combinations in SUVs made by Subaru and Volvo and new designs from Acura, Ford, Honda and Hyundai. Seat/head restraints in three minivan models from Hyundai and Ford also earned good ratings. The redesigned Toyota Tundra is the only pickup model evaluated with seat/head restraints rated good for rear crash protection.

"In stop and go commuter traffic, you're more likely to get in a rear-end collision than any other crash type," said David Zuby, senior vice president of the Institute's Vehicle Research Center. "It's not a major feat of engineering to design seats and head restraints that afford good protection in these common crashes."

The key to reducing whiplash injury risk is to keep the head and torso moving together. To accomplish this, the geometry of a head restraint has to be adequate -- high enough to be near the back of the head. Then the seat structure and stiffness characteristics must be designed to work in concert with the head restraint to support an occupant's neck and head, accelerating them with the torso as the vehicle is pushed forward. Unsupported, an occupant's head will lag behind this forward torso movement, and the differential motion causes the neck to bend and stretch. The higher the torso acceleration, the more sudden the motion, the higher the forces on the neck, the more likely a neck injury is to occur. Such injuries aren't life-threatening, but they can be painful and debilitating, and they account for two million insurance claims each year, costing at least $8.5 billion.

The IIHS ratings of good, acceptable, marginal or poor for 87 current models are based on geometric measurements of head restraints and simulated crashes that together assess how well people of different sizes would be protected in a typical rear crash. The seats in the BMW X5, Dodge Nitro and Suzuki XL7 are rated poor, and the seats in the Cadillac SRX SUV, Nissan Quest minivan and Ford Ranger pickup were all deemed to be so bad the IIHS didn't attempt to test them.

While there hasn't been much overall improvement among pickups and minivans since the last time the Institute evaluated protection in rear crashes, the performance of the seat/head restraints in SUVs is much better. In 2006 those in only six of 44 SUV models earned a good rating; now 17 of 59 models were rated good.

Cleveland-based Driving Today Contributing Editor Luigi Fraschini writes frequently about vehicle safety issues.