Whiplash, that sudden backward snap of the head in a rear-end collision, is one of the most common, painful and costly side effects of minor auto accidents. More than 300,000 whiplash injuries are recorded in America every year, with effects ranging from paralysis and to something as minor as a stiff neck. The key to preventing whiplash involve those pillow-like protrusions at the top of a car seat that most of us call head rests. Safety engineers call them head restraints, and soon you’ll understand why.
Brian O’Neill: “About 25 percent of the dollars paid out by automobile insurers for injuries in the United States are for whiplash injuries.”
That adds up to some $7 billion each year says Brian O'Neill, president of the Insurance Institute for Highway Safety. The Institute, funded by insurance companies is trying to find ways to not only make cars safer, but reduce the amount insurance companies pay in claims.
It recently tested head restraints on 73 cars using a sled that simulates a rear-end collision at 20 miles an hour. A sophisticated test dummy records what might happen to a real person, in this case a large adult male.
O’Neill: “As you can see it has this human like spine. That is designed to respond the way a spine does in a rear-end crash, as this part gets driven forward, the spine tends to straighten up, and then the neck goes back.”
But before a seat was even tested, the Institute's engineers measured each head restraint.
O'Neill: “Still fairly far behind the head, barely high enough.”
The Institute found some weren't high enough or close enough to catch your head, so they couldn't prevent your neck from snapping back in an accident. And other head restraints didn't lock in place when adjusted so they might collapse on impact.
Because they didn't even offer the most basic protection, 24 seats flunk the test before they ever made it down the runway. The rest get to go for a ride. Overall the Institute was very disappointed. Most of the head restraints tested did very poorly. Take the 2005 Toyota Corolla for instance. Its head restraint is too low to protect the dummy's head.
The institute says the seat needs to be almost an inch higher to give more support to the head.And even a seat's softness can make a big difference, for instance, with the 2004 Corolla.
O'Neill: “It did very well, because it's not very stiff here. So the person can sink into the seat.”
In contrast, the BMW seat, with the same geometry, didn't do well because part of the seat is too stiff. And when the seat gets pushed forward, it also pushes hard on the occupant.”
O'Neill says a seat should be like a baseball mitt, so the body is caught and surrounded by the seat's cushion.
And then there are active head restraints. These seat backs are supposed to move forward in a crash. But O'Neill says it doesn't matter what type of head restraint you have if the seat moves too much. Take the Infiniti i35, it has an active restraint.
O’Neill: “There was a lot of rotation of the seatback from the hinge at the bottom. That didn't allow the active mechanism to catch the head soon enough.”
In all, counting those seats that failed before they ever made it to the runway, 54 got the Institute's worst rating, poor -- 19 rated marginal, only one rank above poor and 16 received acceptable ratings. Only eight head restraints received the Institute's highest rating, a “good” rating.
Three Volvos, the S40, the S60 and the S80 all receive good ratings. And what sets these seats apart?
O’Neill: “Basically, this hinge is designed to yield during a crash, so that the seatback goes this way and then rotates when the occupant loads it during a rear-end crash. If you pull on the seat back, we can see that movement and rotation that occurs during a crash. That lowers the forces on the occupant’s torso. So it's equivalent to making the crash less severe.”
The Jaguar S-type has that same type of seat. It also got a good rating. Just four other cars win top honors for their head restraints, the Saab 9-2X and 9-3, the Subraru Impreza and the Volkswagen new Beetle.
And what do the manufacturers say about the Institute's test?
Toyota, Nissan, the manufacturer of the Infiniti i35, and BMW say it is "unclear" if the Institute's test results relate to the actual "probability of injury" in real world situations. All of the manufacturers think their head restraints work pretty well.
As serious as whiplash can be, you'd think the government would have some sort of safety standard to prevent it. And in fact there is one. Every car examined by the Institute passes it. But even the best seat design won't protect if you don't use it properly. The biggest problem is that too many drivers don't adjust their head restraints. Remember, these are head restraints, not head rests. They should sit close to your head, and be high enough to meet the center of your head.
The Institute's O'Neill says both manufacturers and drivers need to take head restraints more seriously. He hopes his tests will make that happen.
O’Neill: “This program will focus the manufacturers' attention on this issue, and I think we're going to see big improvements in seat and head restraint designs in the next few years.”