The Role of Biomechanics in Motor Vehicle Accident Litigation – National Biomechanics Institute

The Role of Biomechanics in Motor Vehicle Accident Litigation


As if Pavlov conditioned you himself, the instant you hear that single syllable jingle, your eyes peer off the road and onto your iPhone — “Hey baby where are you?”


And just like that, you find yourself crunched between your seat, airbags from every which direction (if you’re lucky), and the bumper of an SUV that once seemed miles away. It all happened in a split-second, but you can recall every minute detail of that fateful moment which initially left you gasping for air, and now finds you with a twinge in your neck and incessant headaches.

Once the emotional shock of the accident subsides, you begin recalling with clarity: yes, you rear-ended the car in front of you, but they also slammed on their brakes unexpectedly. And you technically never touched your phone, but rather, that endearing message from your newly minted fiancé popped-up as a notification. So, who’s at fault? And more importantly, who pays for the damages - both to your body, and that of your new car?

There are 11 million MVAs (motor vehicle accidents) annually in the U.S., 400,000 of which result in death. Unsurprisingly, 52 percent of all personal injury lawsuits (i.e. tort trials) result from car accidents. Plaintiffs typically reap a pretty penny too — around $31,000 on average. Unfortunately, it usually takes around 20 months to determine fault, and for money to exchange hands.

As the age-old adage goes, you gotta spend money to make money. In order to prove your innocence, and thus be financially awarded for any damages, you must spend on a multitude of individuals and services — attorneys, actuaries, accountants, administrative fees, court filing fees, the list goes on and on. Oddly enough, those who are tasked with evaluating the cause and severity of injury — and thus the amount of damages awarded — often fly under the radar: expert witnesses.

Expert witnesses include engineers who testify about the physical construction of the car, and accident reconstructionists who recreate (e.g. via animation) the scene of the crash. The complete anatomy of the crash (e.g. speed of the cars, whether seatbelts were worn or not, faulty engineering in the airbags, etc.) is then conveyed to experts in biomechanics.

Biomechanists use all pertinent information to determine injury mechanisms. This can include the rate of impact to the head and transmitted shock to the brain, to the magnitude of blunt trauma to the low back, and shear forces to the cervical vertebrae. This data is then compared and/or extrapolated to thresholds associated with injury. Utilizing previous clinical research, the expected recovery time — and thus, medical expense estimates — can be determined. In conjunction with the engineer, and predicated upon the accident reconstruction and the biomechanical injury determinants, the biomechanist can then provide rationale as to whom was at fault for the sustained injuries — you, the other driver, or the car.

The most common injuries resulting from automobile accidents are to the head, neck, spinal cord, and low back. These are often the result of whiplash. In the common rear-end collision, the rear-impacted occupant’s pelvis and torso are accelerated forwardly in rapid succession. The head is last to accelerate forward, with its acceleration impeded by its weight (i.e. it has a large inertia). The net result is the head actually retracting relative to the spine. In other words, your head and body go in opposite directions. Predictably, even the most benign whiplash events can induce excessively high torques to the spine and strain to the muscles of the neck.

With all that in mind, let’s now recall that (hypothetical) accident of yours. Unfortunately, your lawyer was unable to prove your innocence (this is typical for the front-impacted driver in a rear-end collision). As a result of the collision, the individual whom you crashed into — let’s call him “Mike” — presents with whiplash symptoms to the neck. Accordingly, Mike sees a doctor who prescribes medication and 10 weeks of physical therapy. Are you now responsible to pay for the entirety of Mike’s medical bill?

So here’s some good news: you needn’t worry about getting a part-time job to pay for his medical expenses. See, the biomechanics consult revealed that the direction, rate and total impact to Mike’s head and neck were nominal. In fact, previous clinical trials have reported spontaneous recovery of whiplash within 48-72 hours for similar crashes. Sad as it may seem, it appears that Mike was lying about the severity of his injury in order to collect some cash — something that’s not all too uncommon in MVA personal injury cases.

Though you just saved thousands, you still find yourself down in the pits with a strained neck and terrible headaches (not to mention a damaged fender). So hopefully this relieves a bit of stress — the engineering expert found that your front airbag deployed 3/10 of a second too late, causing your head to displace too far forward (i.e. exacerbating the whiplash event). The biomechanist determined that this led to a 30 percent increase in strain to the upper trapezius muscles, explaining the stiff neck and associated headaches. What it all means: you’re still responsible for that fender, but your car manufacturer better fork up for your medical bills.

We all recognize the stress associated with motor vehicle accidents. Maybe even more stressful than dealing with the injuries themselves is managing the exorbitantly high and ever-increasing medical costs. Fortunately, proper expert evaluations of the crash may prove your innocence and help mitigate the financial damages. Now, buying a hands-free device to prevent you from looking down at your iPhone altogether? Well, that one’s on you.