• Jul 3, 2007
Over the past few years, the Insurance Institute for Highway Safety (IIHS) has been testing the effectiveness of head and neck restraints in most of the new models that it puts through its battery of batterings, and with good reason. Rear-end collisions are the number one crash on American roads. The latest round of tests reveals that over 60-percent of new trucks, SUVs and minivans are scoring either marginal or poor.
Of 87 models tested, 54 vehicles failed the test, while only 21 received the 'Good' rating from the IIHS. Among them was the new Toyota Tundra, whose previous four-star crash rating from the government was a blow to automaker's newest entrant into the highly competitive truck segment.

Several other vehicles have improved their scores, including the Acura MDX, Honda CR-V, Element and Pilot, the Hyundai Santa Fe, Kia Sorento and Mercedes M-Class. The BMW X5, Dodge Nitro and Suzuki XL7 all were rated as 'poor.'

You can read the IIHS press release in full after the jump, and you can see a video that explains the testing procedures by clicking here.

[Source: IIHS]

PRESS RELEASE

Rear crash protection in SUVs, pickup trucks, & minivans: most of their seat/head restraints are marginal or poor

ARLINGTON, VA - 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 latest evaluations of occupant protection in rear-end collisions by the Insurance Institute for Highway Safety 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.

The 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.

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 3 minivan models from Hyundai and Ford earn 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," says 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."

Rear-end collisions are frequent, and neck injuries are the most common injuries reported in auto crashes. They account for 2 million insurance claims each year, costing at least $8.5 billion. Such injuries aren't life-threatening, but they can be painful and debilitating.

Good seat/head restraint designs keep people's heads and torsos moving together: When a vehicle is struck in the rear and driven forward, its seats accelerate occupants' torsos 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, and the more likely a neck injury is to occur.

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.

SUVs improve: In the latest evaluations, the seat/head restraint combinations in 17 of 59 SUV models are rated good, 5 are acceptable, 14 are marginal, and 23 are rated poor. In minivans, seat/head restraints in 3 models are rated good, 2 are acceptable, 1 is marginal, and 5 are rated poor. In pickups 1 is good, 5 are acceptable, 5 are marginal, and 6 are rated poor.

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 6 of 44 SUV models earned a good rating.

"The reason may be that automakers have updated or introduced many new SUVs since 2006, but minivans and pickups are being updated more slowly," Zuby points out.

In the latest tests seat/head restraints in the Mitsubishi Outlander improved to good from the previous design that was rated acceptable. Those in the Acura MDX, Honda CR-V, Honda Element, Hyundai Santa Fe, and Kia Sorento improved from their previous ratings of poor to good. Those in the Honda Pilot and Mercedes M class improved from marginal to good. The seat/head restraints in the Toyota Tundra pickup improved to good from acceptable.

In contrast some manufacturers have introduced new models with subpar seat designs. The ones in the BMW X5, Dodge Nitro, and Suzuki XL7 are rated poor. Those in the new Mazda CX-7 and CX-9 are rated marginal.

Among the poor-rated seats in the new evaluations, those in 7 models didn't make it to the testing stage because the geometry of their head restraints is marginal or poor. This means they can't be positioned to protect many taller people, so the Institute doesn't test them. Among these lowest rated seats are those in the Cadillac SRX SUV, Nissan Quest minivan, and Ford Ranger pickup.

Safety ratings and government rules are driving the changes: Some manufacturers are making changes to the seat/head restraint designs in their vehicles to earn the Institute's TOP SAFETY PICK award. Other improvements are being spurred by changes to federal safety rules. Front-seat head restraints will have to extend higher and fit closer to the backs of people's heads under a rule issued by the National Highway Traffic Safety Administration in 2004. Originally set to go into effect for front-seat head restraints in September 2008, the agency recently delayed the effective date in response to petitions for reconsideration. Under the new phase-in schedule, manufacturers must start to fit better front-seat head restraints in 80 percent of their models beginning in September 2009. Front-seat head restraints in all new vehicles made after September 2010 must comply.

"There's lots of room for improvement in the designs of seats and head restraints," Zuby says. "We know many manufacturers are trying to fit better head restraints in their vehicles, and some have been working with us to boost their ratings as they introduce new models. Some manufacturers were waiting for resolution of regulatory issues before fitting better designs in their vehicles. And some didn't get changes made in time for the Institute's tests. For example, BMW plans to redesign the seats in the X5 and X3 SUVs to earn better ratings for the 2008 model year."

The Institute's procedure for evaluating the geometry of seat/head restraints is used worldwide by the Research Council for Automobile Repairs, an international consortium of insurance-sponsored research centers. US federal crash test ratings don't evaluate seat/head restraint designs, but the National Highway Traffic Safety Administration has expressed interest in exploring adding the Institute's seat/head restraint ratings to its website that publishes New Car Assessment Program results. In Europe, the European New Car Assessment Programme is considering adding a head restraint evaluation component to new vehicle assessments.

"The Institute's evaluations of seat/head restraint designs suggest that the worldwide attention is yielding results," Zuby says. "We're seeing more seat/head restraints rated good and acceptable than we used to. It's clear that many foreign and domestic automakers are moving in the right direction."

Sled test simulates rear-end collision: Seat/head restraint ratings are based on a 2-step evaluation. In the first step restraint geometry is rated using measurements of height and distance from the back of the head of a mannequin that represents an average-size man. Seats with good or acceptable geometric ratings are subjected to a dynamic test conducted on a crash simulation sled. This sled test replicates the forces in a stationary vehicle that's rear-ended by another vehicle of the same weight going 20 mph, which accelerates the struck vehicle to 10 mph. The sled is a movable steel platform that runs on fixed rails and can be programmed to recreate the accelerations that occur inside vehicles during real-world crashes.

A dummy specially designed to assess rear-end crash protection, BioRID, is used to measure the forces on the neck during the simulated crashes. Researchers also measure how hard the seatback pushes on the dummy's back and how quickly the head restraint supports the head.

The Institute's dynamic ratings of good, acceptable, marginal, or poor are derived from two seat design parameters (peak acceleration of the dummy's torso and time from impact initiation to head restraint contact with the dummy's head) plus neck tension and shear forces recorded on BioRID during the test. The sooner a restraint contacts the dummy's head and the lower the acceleration of the torso and the forces on BioRID's neck, the better the dynamic rating. A seat/head restraint's dynamic evaluation is combined with its geometric evaluation to produce an overall rating.


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    • 1 Second Ago
  • 11 Comments
      • 7 Years Ago
      "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."

      Kudos to Subaru. I wish Subaru got more recognition in the minds of the common public with respect to their safety record.
      • 7 Years Ago
      It's cool, I just wanted to make it clear where I was coming from. So many people post hard to read one-liners here that eventually it gets to me ;)
      • 7 Years Ago
      Don't get me wrong, I've been an avid IIHS fan for years, pointing many in their direction when evaluating a vehicle purchase. Having said that the rear impact rating is a ridiculous farce and far too subjective based on the seating position. Furthermore the "dynamic" test isn't in a vehicle, it's on a test platform and completley leaves out of the equation the actual vehicle design and rear impact performance only to focus on seat design.

      The IIHS themselves does not display it's rear impact ratings prominently on a vehicle rating page, rather it hides the rear rating on a seperate site by manufacturer. This is speculation but I suspect there is even interal rift in the IIHS over the rear impact ratings.

      To get an idea of how subjective the ratings are and why this is such a farce one has to do nothing more than read this is a quote from the IIHS test procedure: "The rating for a head restraint that adjusts in height and/or backset depends on whether it locks in the adjusted position. If it doesn't lock, its rating is defined by its height and backset in the down and/or rear position. If it does lock, height and backset are measured twice — in the down position, and in the most favorable adjusted and locked position. The final rating is the better of the two, except that if the rating as adjusted is used, it's downgraded one category because so few motorists adjust their restraints. "

      It's too bad they are pushing these rear ratings because, at least in my eyes, this weakens their previously stellar credibility.

      Facts:
      http://www.iihs.org/ratings/head_restraints/head_restraint_info.html
      • 7 Years Ago
      TOYOTA TUNDRA ONLY TRUCK WITH TOP RATING........CHEVY AND FORD? POOR RATING.
        • 7 Years Ago
        Holy crap, you can't read. Stop putting words in my mouth. I never said that "good" wasn't the best score. I know full well that it is. That didn't stop the IIHS from saying that other vehicles were the "best" overall, meaning they likely scored "good" in several tests, rather than just one or two.

        Since you started using full sentences, I'll reference what you said: "Being the only truck with a 'good' rating definitely makes it top in its class in that regards." I completely agree, because you said *in that regards*. Toyota Tundra was tested as the best in that regards. What I was saying about the Ford and GM trucks has to do with their overall rating; this very specific test of the headrest when the car is hit from the rear isn't what I was talking about.

        To repeat what I said, "You picked one small positive thing about the Tundra and appear to be ignoring everything else."

        For the record, I'm not a laid-off Big 3 union worker. I have two separate bachelor degrees from one of the top schools in the country for those fields, and am almost finished with graduate school. I seriously doubt I need any more "education," especially to post on Autoblog.

        This has been a waste of time though, mostly because you spoke in sentence fragments at first, and then proceeded to misconstrue both of my posts in response. If you would've posted something along the lines of your 3rd post first, we wouldn't be in this situation.
          • 7 Years Ago
          my apologies bro...I don't mean everything I say on autoblog.

          Peace!
        • 7 Years Ago
        Yes, I read *the* article. Work on your grammar. Some select quotes:

        "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 3 minivan models from Hyundai and Ford earn good ratings." Toyota isn't on that list of best performers. Ford is.

        It did say "The redesigned Toyota Tundra is the only pickup model evaluated with seat/head restraints rated good for rear crash protection." That's all well and good, but apparently wasn't good enough to get overall top safety scores, which the Chevy and Ford did get.

        Chevy and the Silverado weren't even mentioned anywhere in the post, good or bad. You picked one small positive thing about the Tundra and appear to be ignoring everything else.

        If you (re-)read what I said, I never actually asked a question either, let alone a stupid one. I pointed out that what you wrote wasn't understandable - not even a sentence.
          • 7 Years Ago
          Einstein! Do you have any idea how IIHS rate vehicles. "Good" is the highest possible rating. Being the only truck with a “good” rating definitely makes it top in its class in that regards. I believe an eight year old would understand that.

          You are probably a laid-off Big three worker. ... You should probably get some education and quit the unions if you want to help the big three.

          nuff said, talking to you is a waste of time.
        • 7 Years Ago
        I am completely unsure of what you're trying to say. I guess you prefer the Tundra to the F-150 and Silverado, but saying the Tundra has the top rating and the others don't is an utter lie, since it's the other way around. Putting the entire message in caps and then failing to use a verb (let alone a few articles) doesn't really make it look like you know how to talk to people.
          • 7 Years Ago
          Moron...did u read article? If you did, you wouldn't be asking stupid questions
      • 7 Years Ago

      Among them was the new Toyota Tundra, whose previous four-star crash rating from the government was a blow to automaker's newest entrant into the highly competitive truck segment.

      I still would prefer an F-150 or Silverado over a Tundra regardless of this.