Safety Tips

Protect Your Neck: Warding Off Whiplash With Head Restraints
By Warren Clarke, Automotive Content Editor
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You're whizzing along on the freeway, pondering everything and nothing in particular, savoring the guilty pleasure of some over-rotated pop ditty on the radio. Suddenly, the brake lights of the car in front of you gleam blood red, indicating an abrupt slowdown in the flow of traffic. Goodbye, reverie; responding quickly, you slam your foot to the brake pedal. There's enough distance between your car and the vehicle that precedes it to avoid a collision. But the tailgater behind you isn't as lucky, and his front bumper comes hurtling into the rear of your vehicle.

CRUNCH! In a flash, the impact causes the back of your seat to be pushed forward into your torso, straightening your spine and forcing your head to rise vertically. Then your head is tossed violently backward like a shaken rag doll's, continuing to rotate as your neck muscles, cartilage and bones vainly attempt to resist the jolt.

At the end of it all, you're stuck with more than just a damaged vehicle. Though the accident was a relatively minor one, it's left you with whiplash, a condition affecting the ligaments and muscles of the neck and shoulders. Typically caused by rear-end collisions, whiplash can cause lasting distress and discomfort.

At the very least, it's a major pain in the neck. But it didn't have to be that way. A properly configured head restraint system could have prevented your injury.

So what exactly are head restraints, anyway? Head restraints are extensions of vehicle seats. They're those things that most people think of as headrests, but that's not really their primary function; they were actually designed to restrict head movement during a rear-impact collision. In doing so, they reduce the chance of neck and shoulder injury. They're an important (though often overlooked) safety feature, and, since 1969, cars have been federally mandated to have head restraints in the front seating positions.

Most vehicles contain head restraints that are of the manually adjustable variety. Under current federal law, head restraints must be adjustable to 27.5 inches above a vehicle's seating reference point (defined by a test machine placed in the seat). This regulation governs the stature of the head restraint when it's at its highest — in the "up" position.

But what about restraints left in the "down" position? Research has shown that most drivers with adjustable restraints don't take the time to configure them properly, leaving them at their lowest. The result? The head restraints are rendered ineffective, since restraints left "down" are typically 2 to 4 inches lower than the current federal regulations dictate. In the event of an accident, unadjusted restraints provide little or no protection against neck injuries.

There are some who would like to make the federal standard even higher. An upgrade has been proposed that would bring the U.S. laws in line with height requirements of the more stringent European standard. The updated U.S. rule would cover horizontal placement, as well, requiring head restraints to be close to the head of the person seated. This is in line with studies that have shown that restraints are most effective when they are close to the head horizontally as well as being properly positioned vertically.

The new law mandates restraints at 29.5 inches above the seating reference point, even when left at their lowest position (effectively dealing with the issue of unadjusted restraints). The distance between the back of an occupant's head and the front of the restraint would be limited to 2 inches.

Future legislation is all well and good, but you're probably wondering what you can do to best protect yourself now. If you've got a vehicle with a manually adjustable head restraint, make sure that the restraint is always in the correct position. According to the National Highway Traffic Safety Administration (NHTSA), to be effective, the top of the restraint should lie somewhere between the top of your ears and the top of your head. If the restraint articulates for horizontal adjustment, it should be placed so that it's as close to your head as possible, without pushing your head forward or causing the height of the restraint to drop.

Though manually adjusted head restraints are part of the package on most vehicles, there are alternatives available. Some vehicles offer restraint systems that adjust automatically with changes in seat position; others offer systems that adjust dynamically in a crash. Of the three types of restraints available — manual, automatic and dynamic — there is one that is viewed as being, well, head and shoulders above the rest when it comes to effectiveness; according to the NHTSA, dynamic restraint systems are your best bet when it comes to ensuring adequate protection from neck injury in a crash.

It's easy to see why. Dynamic head restraint systems take an active approach to injury prevention; they're designed to deploy automatically in the event of an accident. They also reduce the whiplash-inducing abrupt motion of the head and torso that can take place during a collision by utilizing more than just head restraints. The seatback is also incorporated into this system, creating a mechanism that cradles and supports the head and torso in the event of a sudden impact. Volvo and Saab have been pioneers when it comes to integrating this type of system into their vehicles; for the past couple of years, virtually all of their cars have featured dynamic head restraint systems. To gain a better understanding of how these neck-savers work, let's take a look at the systems offered by these two manufacturers.

The key component in Volvo's Whiplash Injury Prevention System (WHIPS) is a hinge at the base of the seatback. This hinge yields and partially rotates when an occupant's torso makes the sort of impact associated with a rear collision, moving the seatback rearward — thus reducing forward motion of the torso. WHIPS also features a fixed head restraint with effective geometry, meaning one that sits high and close to the head; this restraint catches the head in an accident, enabling it to move forward with the torso. Reduced torso acceleration and the head restraint's quick reduction of head movement mean that the neck changes shape less — and the change occurs more slowly — than with a conventional seatback/head restraint. The result? Whiplash is less likely to occur.

Saab's Active Head Restraint (SAHR) is based on the lever principle. A padded head restraint is linked to a pressure plate inside the seatback. When a rear-end collision causes the torso to make impact with the seatback, force is exerted on the plate; this sends the head restraint moving up and forward, enabling it to catch the occupant's head before the motion that induces whiplash has a chance to begin. Additionally, the seatbacks themselves feature crossbars and padding designed to absorb crash energy and cradle an occupant's torso, reducing differential movement between the head and torso.

Which 2007 vehicles, besides Volvo and Saab, offer dynamic head restraint systems? A list of such vehicles, obtained from the NHTSA, follows:

Acura	MDX
	RDX
	TL
Audi	A3
	A4
	A8
	Q7
	RS4
	S4
	S8
BMW	7 Series
	ALPINA B7
Honda	Civic
	CR-V
Hyundai	Azera
	Elantra
	Entourage
	Santa Fe
	Sonata
	Veracruz
Infiniti	FX35
	FX45
	G35
	M35
	M45
	QX56
Jaguar	S-Type
	XJ-Series
	XK-Series
Jeep	Grand Cherokee
Kia	Amanti
	Optima
	Rondo
	Sedona
	Sorento
Land Rover	Range Rover
Mazda	MAZDA3
	MAZDA6
	MAZDASPEED 3
	MAZDASPEED 6
Mercedes-Benz	C-Class
	CLK-Class
	CLS-Class
	E-Class
	GL-Class
	M-Class
	R-Class
	S-Class
Mitsubishi	Outlander
Nissan	350Z
	Altima
	Altima Hybrid
	Armada
	Frontier
	Maxima
	Murano
	Pathfinder
	Quest
	Sentra
	Titan
	Versa
	Xterra
Rolls-Royce	Phantom
Saab	9-3
	9-5
Subaru	B9 Tribeca
	Forester
	Impreza
	Legacy
	Outback
Toyota	Highlander
Volkswagen	GTI
	Jetta
	New Beetle
	Passat
	Rabbit
Volvo	C70
	S40
	S60
	S80
	V50
	V70
	XC70
	XC90

So far, we've looked at head restraints as they pertain to the driver, and those riding in front. But what about passengers in the back seat? Head restraints can serve to protect them from injury, as well. Most cars provide head restraints for their rear seat passengers (a notable entry without them is the Ford Focus), but the Volvo S80 is the only car to offer active head restraint technology for both front and rear passengers.

So the next time you get into your car, or consider buying a vehicle, give some thought to the head restraints perched atop those seatbacks. They could very well wind up saving your neck someday!