Effect Measure

Crashworthiness and whiplash

When I recently got rid of my 15 year old car for one that is only 2 years old, I was amazed and impressed at the number of genuine safety features, many of them hidden or not obvious. Cars are simply much safer now than they were, even a decade ago, not to mention when I was a youth. Here’s a dramatic example comparing the crashworthiness of a 1959 Chevy Bel Air and a 2009 Chevy Malibu:

Injuries are the major cause of death up to age 44 and the most frequent cause is motor vehicle accidents. Car crashes also cause injury and disability, and one of the more common comes from the sudden acceleration of the head in a collision followed by a sudden deceleration. You can clearly see both in the video. The resulting transfer of injury to the cervical spine causes the notorious whiplash injury. Long a staple of anti-personal injury lawyer barbs, whiplash itself is no joke, and while head restraints have improved the situation, there is still a some way to go. Many times they are improperly positioned and can change position in a crash. A recent paper in the International Journal of Vehicle Systems Modelling and Testing describes a new Italian design that allows optimum positioning and locks the headrest in place during a collision:

Part of the problem is the drivers and their passengers are unaware of the personal harm a whiplash injury can do and usually fail to adjust their headrest to the optimum height. Moreover, common headrests are often difficult to adjust and are pressed downwards by the head in a collision and so do nothing to save the person from injury. A headrest that can be adjusted without fuss to the optimum safety and comfort level is needed, the team says. The team has studied the biomechanics of whiplash injury, so named because of the way the head moves when involved in a rear-end collision. (ScienceDaily)

There is no picture of the head rest. But one of the things I’ve observed about car safety features is that many are designed, like this one, to mitigate the effects of an accident, with less attention to their possible effect on causing the accident. Both the headrests and the aerodynamic designs of modern cars for fuel efficiency have the effect of interfering with visibility. So while I might be safer after the crash, I am more likely to get into a crash because I can’t see the vehicle in my blind spot. I am quite paranoid about the blind spot and routinely turn my head before changing lanes, but recently I’ve rented some cars where even turning my whole body to look through the right rear window didn’t help because of the positioning of the roof supports at the rear (the Subaru Impreza was especially bad in this regard). The idea that a good head restraint design will reduce whiplash is plausible but remains to be seen. But at the same time I hope they are taking into account the other aspects of the intricate but taken for granted set human factors we call “driving.”

Maybe I’ll send them a text message the next time I think of it when I’m on the road.

Comments

  1. #1 Comrade PhysioProf
    December 29, 2009

    Risk compensation is also a major factor to be considered in assessing “safety improvements” to consumer products like automobiles. For this reason, the actual improvements in safety are always smaller than theoretically predicted, because people react to greater perceived safety by behaving less safely.

  2. #2 BostonERdoc
    December 29, 2009

    As an ER doctor practicing in a busy trauma centers for the past 15 years, I rarely see whiplash. Some believe it is primarily a lawyer based diagnosis more so than medical diagnosis. Worst case senario of sudden deacceleraton is diffuse axonal (DAI) injury (brain axons that is) or tearing of the thoracic aorta. We typically see this about 20-30 times a year in our shop–mostly showing up dead from the torn aorta or life ruining head injury from the DAI head injury. You are definitely right about hidden car safety features– they have taken a lot of business away from me. Most trauma mainly involves baby sitting in the CAT scan suite rather than trip to the OR. Seems nobody dies when they are in a Chevy suburban or Volvo. Older model Saabs are the safest in regions where Moose are because the A frame is well built with reindeer collisions in mind (apparently frequent in Sweden)and stiking a moose is similar to reindeer. We just had a case of this in early December in the greater Boston region of all places. I am holding out buying a new car for another 3 to 5 years. By that time the heads up instrument, panel, and out of lane automatic correction features will be up and running making the trauma centers less populated. In any event enjoy your new set of wheels Revere.

  3. #3 glock
    December 29, 2009

    FWIW , I find most drivers ignorant of the ideal positioning of
    side view mirrors to maximize visibility. Most find it important
    ( or maybe comforting) to see the sides of their vehicle when they
    glance in the mirrors. You want to see the adjacent lanes on
    either side, WITHOUT moving your head.

    Ideally, if in the center lane of a 3 lane highway, where you lose sight
    of an overtaking vehicle in the rearview mirror, is where you should
    pick it up in the side view mirror, and where you lose sight of it in the svm
    is where your peripheral vision should pick it up.
    You should NOT have to move your head.
    Ideally that is, notwithstanding shitty automotive design.

    Great video BTW, we have come a long way…. with more to go.

  4. #4 Otto
    December 29, 2009

    Somehow I yearn for an International Harvester Scout 800 all the same.

  5. #5 Tony P
    December 29, 2009

    In 1985 I was driving a 1976 Mercury Monarch. I got t-boned. No seatbelts of course, I was 17 years old at the time. I ended up with 11 stitches in my head but no concussion. Blood everywhere though, head injuries are a real horror show.

    That was my first ride in a rescue vehicle. By the time I got to Our Lady of Fatima the bleeding had pretty much slowed down and I was fully lucid and anxious to get this patched up.

    The reason I was anxious, I had to go on the air at midnight. You had to see me, on a hospital gurney next to a phone so I could call me on-air partner and tell him what happened.

    When I saw the car later, it was a shock. It looked like the letter A without the cross member.

    Yeah, that car wasn’t built with crumple zones. But then no car will crumple from the side.

  6. #6 Margaret S.
    December 29, 2009

    Further to #3 @glock, I agree. I learned to drive in the early 1970’s, and I was taught to shoulder-check (turn around to check the blind spot). In those days, passenger-side mirrors weren’t standard, and driver-side mirrors could only be adjusted by reaching a hand outside to adjust the mirror directly (and it was stiff and hard to get into the right position). There definitely was a blind spot that was impossible to cover with mirrors, and a safe driver was supposed to turn their head to check it.

    I don’t know when today’s style of side mirrors became standard equipment, but for sure my generation and older ones weren’t taught to adjust the mirrors properly to cover the blind spot in the way you describe. I am slowly training myself to properly position the mirrors and to use them instead of shoulder-checking but it’s hard to change decades of habit.

  7. #7 Paula
    December 29, 2009

    BostonERDoc–I don’t know how much lawyers lash the whip, so to speak, but ten years ago, stopping quickly at an intersection, I felt my car slide a bit sideways. An hour later, at work, I started getting a headache; sure I was sick, I drove home, by evening could not even lean my head somewhere without pain. It wasn’t meningitis and no other symptoms and 3 physicians were stumped; 3 or 4 days later, healing, I remembered the slide, looked up whiplash online, and there were the exact symptoms. Doesn’t take an attorney sometimes.

  8. #8 caia
    December 29, 2009

    BostonERDoc — I don’t know about whiplash, but my experience with back muscle injuries has been that they aren’t always immediately apparent. If you’re saying that you don’t hear about whiplash from people being seen within an hour (or several) of an accident, my response is that I’m not surprised.

  9. #9 Katy
    December 31, 2009

    A few years ago, Click and Clack had a great piece on Car Talk about rear view mirror positioning so that there is no blind spot. It takes just a few minutes and works. Now I see they have a whole section of their website dedicated to this and a pdf on the procedure.

    http://www.cartalk.com/content/features/mirrors/

    Safe driving!

  10. #10 Oran Kelley
    December 31, 2009

    Risk compensation is also a major factor to be considered in assessing “safety improvements” to consumer products like automobiles. For this reason, the actual improvements in safety are always smaller than theoretically predicted, because people react to greater perceived safety by behaving less safely.

    What is “perceived safety?” How do you measure it and what causes it? It surely is not a rational analysis of the actual risks being undertaken.

  11. #11 glock
    December 31, 2009

    Katy,
    That’s exactly what I was trying to convey. As usual Click & Clack do a better job of explaining the process. Though I still prefer to do it on the highway. Nice find.

  12. #12 tymbuktu
    December 31, 2009

    For the ER doc who THINKS he isn’t seeing any whiplash injuries I would think he would know better that the effects usually don’t present for 48 to 72 hours. Being the unfortunate victim of 4 rear-end collisions in which all four the police and insurance company apportioned me zero blame, my life has been forever changed by being hit. Twice I was in a Volvo, the other in a Camry and a Taurus as both a driver and passenger. I always wear my seat belt properly.

    As I write this I am hooked up to a portable RS Medical muscle stimulator which I alternate with a TENS unit and when especially bad, Vicodin. So please do not try to impune the reputation of those who are injured this way. I would much rather have had several broken limbs that a soft tissue and possible MTBI.

  13. #13 tense
    January 8, 2010

    Glock: I found out how to set my mirrors from a Popular Science Mag a Long time ago! It has literally saved mine and other lives too Many times to remember!

    For the Left side mirror: Lean your head to the left, touching the window, set your mirror to see straight up the side of the car.

    For the right side mirror: lean your head to the centre of the car and set the mirror to see straight up the side of the car.

    For those who have never done this it is real hard to get used to, till the first time it saves them when they change lanes!