Toyota TundraClick to enlarge picture

The 2007 Toyota Tundra is the only pickup truck to earn a top "good" rating for seat/head restraint rear-crash protection for passengers.

Despite the considerable weight and size of these kinds of vehicles that convey a sense of safety, more than one third of 59 SUVs analyzed by an insurance industry group had seatback and head restraint combinations that rated only "poor" for proper head and neck support. This means that passengers in those seats could be at higher risk for whiplash injury.

Among the poor performers are the 2006-2007 Hummer H3, 2004-2007 Lexus GX 470, 2005-2007 Nissan Xterra and 2003-2007 Toyota 4Runner.

The Insurance Institute for Highway Safety (IIHS) also analyzed pickups. Only one of the 14 evaluated—the 2007 Toyota Tundra—earned the top "good" rating, while bestsellers like the 2004-2007 Ford F-150 with integrated seatbelts received a "poor" rating.

Is It A Big Deal?
Rear-end crashes are more frequent than most of us realize—occurring every 17 seconds in the U.S., said Consumer Reports magazine which also analyzed vehicle head restraints for its August 2007 issue.

And while fatalities are rare in these kinds of crashes, whiplash injuries are a major problem, involving 2 million insurance claims per year, according to the IIHS, based in Arlington, Va.

Indeed, pain and lack of flexible movement resulting from whiplash can disable victims—young and old—for years.

Note that it doesn't matter how many airbags a vehicle has, because current airbags are not designed to deploy in rear-end crashes. Generally, they work to provide injury protection in frontal, side and rollover crashes.

Measuring Rear-Crash Protection
The U.S. government doesn't publish rear-crash protection data.

And the IIHS didn't run actual car crash tests. Instead, institute researchers looked at the geometry of seats and head restraints the way the Research Council for Automobile Repairs does—in two steps.

First, height and distance measurements are made using a head of a mannequin representing an average-size man.

Then, seat/head restraints with acceptable geometric ratings from the first step are subjected to dynamic testing on a crash simulation "sled" in a laboratory.

Improvements Coming
The IIHS report and Consumer Reports' information show that while some automakers have been improving interior rear-end crash protection, others have not yet made updates.

And buying a new model on the market doesn't guarantee the best rear-crash protection. The IIHS cited the Dodge Nitro, which was new for the 2007 model year, as an SUV with "poor" rating. And the new-for-2007 Mazda CX-7 and CX-9 crossover SUVs earned only "marginal" ratings.

How much a car owner pays for a vehicle also doesn't automatically translate into the best seatbacks and head restraints.

For example, the IIHS highlighted the seats in BMW's 2007 X5 SUV as subpar in whiplash protection.

With a starting manufacturer's suggested retail price of $45,900, the X5 is a premium SUV with many technological features. But the IIHS noted BMW plans to "redesign the seats" in the X5 as well as the lower-priced BMW X3 for the 2008 model year.

Automakers also face more stringent requirements from the federal government for the 2009 model year, Consumer Reports said. Head restraints have been mandated on outboard front seats in passenger vehicles since 1969. But they're still not required in back seats, and the shape, size and location of head restraints continues to vary from vehicle to vehicle. Car seats also vary widely.

Head Restraints Work With Seats
Seats and head restraints typically work together to provide needed support in rear-end crashes.

The force of such a crash pushes a passenger's body forward, with a person's heavy head usually lagging behind the torso's motion a bit. Depending on the seat, head restraint, passenger positioning and crash impact, the mixed body reaction can cause a person's neck to stretch and contort, resulting in whiplash injuries. This is true even with passengers who wear their seatbelts.

So seats and head restraints are crucial for keeping the head and body aligned as much as possible as a rear-end crash occurs.

Safety advocates said the best head restraints need to be high enough and close enough to the head to work properly, and seatback structures and stiffness must complement the head restraints.

It also is important for passengers to adjust their head restraints properly when they take a seat, if the restraint is height- and angle-adjustable. The rule of thumb, provided by Consumer Reports, is the top of a head restraint should be at least even with the top of your ears, and the restraint should be within 3 inches of the back of your head.

Back Seats Can Be Problematic
Consumer Reports minced no words in calling the back seats in vehicles "the Wild West" for rear-crash protection.

Some vehicles don't have head restraints back there for all passengers. Some have so-called built-in head restraints that can't be adjusted and are "little more than bumps on the top" of the seatbacks, Consumer Reports said.

Some vehicles have adjustable head restraints that don't lock into place, so they are prone to dropping down and low when pressure is put on them.

At the other end of the spectrum, some head restraints are so sizable they can block driver views out the rear window.

Consumer Reports said it preferred head restraints by Volvo, which can be folded down over the rear seatbacks when not in use. These folded-down restraints also force rear-seat passengers to use the head restraints upon entering because it's too uncomfortable to sit back there with the folded head restraints jammed into passengers' backs.

Even Some Minivans Are Lacking
The most people-friendly of vehicles—minivans—had some problems getting "good" ratings from the IIHS.

Among the 11 minivans examined, seat/head restraints in only three minivans rated "good." They are the 2004-2007 Ford Freestar with fixed head restraints, the 2005-2007 Freestar with adjustable head restraints and the 2007 Hyundai Entourage with active head restraints.

Popular-selling models like the Dodge Caravan and Honda Odyssey rated lower.

Top-rated SUVs, pickup trucks, minivans for rear-crash seats/head restraints (in alphabetical order)

Source: IIHS

Ann Job is a freelance automotive writer.

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