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Putting the 5 MPH Threshold to the Test In a Car Accident

Women On Phone With Wrecked CarIn dealing with Boston car crash cases, occasionally you will read a report that says the patient could not have been injured because the car didn’t have any damage. I find that a fascinating statement. I never learned in chiropractic college that you could examine a car to determine injuries to the occupants of that car. In watching sports, I have seen football players get concussions without any damage to their helmet. I have seen egg cartons look fine with a broken egg inside. Why would a car crash be any different?

Low Impact Collision Cause Injury?

Many times, investigators use creative math to determine that the crash happened at less than 5 mph, so the force could not have caused the injury. That is only a very small piece of the evidence in a car crash. In an article published in the September 2006 Personal Injury Law Journal, a forensic collision investigator, Brian Henderson wrote a very nice piece to address this important issue. Mr. Henderson, the managing director of GBB Ltd Forensic Collision Investigation and Research examines the amount of change in speed needed to cause injury. Mr. Henderson states that “Historically, the argument about injury or likelihood of injury had been the domain of medical experts, albeit without any true scientific evidence on which to base an opinion.

A struck vehicle will accelerate forward, with or without vehicle damage. This will cause accelerations of the occupant’s chest and head.

Mr. Henderson and his colleagues have produced crashes resulting in a change in velocity of 5.97 mph of the struck vehicle. This caused:

  • 4.7 g acceleration of the occupant’s chest
  • 8.3 g acceleration of the occupants head
  • The difference between the head and chest acceleration was 3.6 g
  • This resulted in symptoms of strains and headaches

Mr. Henderson states: “It is my opinion that beyond a speed change of 5 mph, the risk of injury is high.” The risk of injury between 3 mph and 5 mph speed change is a grey area that would need further exploration and injury cannot be ruled out. The risk of injury below 3 mph is minimal.”

Low Impact Car Accident Important Notes

One important note is that not all occupants will react in the same manner to the same change in velocity. This bring us to discuss the other factors that deal with the victim and the details of the crash. Those will include:

  • AWARENESS: the most important factor. Those who are unaware get hurt more.
  • FEMALES: get hurt more than males because they usually have a smaller neck diameter.
  • SIZE OF THE VEHICLES: Smaller vehicles getting hit by larger vehicles is a bad situation.
  • ARTHRITIS IN THE SPINE OF THE VICTIM: arthritic spines are stiffer and less able to handle the impact.
  • IMMEDIATE ONSET OF PAIN: These people are at high risk of being in chronic pain the rest of their life.

Documenting the injuries that occur can only be performed by someone who is trained to look for them. Ligament laxity testing, neurosensory testing and digital range of motion testing are some of the diagnostic testing that can detect these injuries, creating demonstrative evidence. Make sure if you get into a car accident, that you come in to the office an get checked out ASAP. The research says that 20% of the people injured in car accidents do not feel the pain for days, weeks and even years later.

Call Dr. Quigley at 617-720-1992 to discuss your case.   His expert opinion reports have been known to help protect the rights of car crash victims.

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2 Join the Conversation

  1. Fernando Rex Licea, PPIA says
    Sep 29, 2022 at 7:44 PM

    Surely this does not apply to every scenario: for example a sideswiped from a dead stop at a traffic light 0 MPH to 5 MPH on a Left Rear Fender truck. is not going to to cause bodily injury. to the driver and passengers. because the driver only realized the that event took place. 3 minutes after it happens.

    • says
      Oct 12, 2023 at 1:05 PM

      Each case has it's individual factors. Trucks that have steel frames have a much different impact response as well. Happy to discuss the case with you. Call my office at 617-720-1992.

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