Most personal injury lawyers have represented clients suffering from the chronic consequences of concussion and musculoskeletal injuries following a rear end collision that caused minimal damage to the vehicles involved. This blog has reported on countless scientific studies showing that in some patients concussions can have long-term, chronic consequences. The standard defense employed by insurers in minimal damage rear end collisions (which they call “MIST” cases) is to argue that any injury is improbable in these accidents because the forces involved are similar to the forces involved in many activities of daily living (ADLs) where injuries rarely occur (like sitting down in a chair or sneezing).
The insurers and their defense counsel typically have an “accident reconstruction” expert they routinely use (often retired police officers) who calculate the speed change in the crash (the “delta V”) and then compare it to the delta V involved in everyday activities. (The delta V calculations by these so-called experts is often inaccurate, but that is a different issue.) Experience shows that this testimony can be very compelling to a jury, faced with judging the credibility of an injury victim whose injury is not immediately apparent.
A new peer-reviewed article in the International Journal of Environmental Research and Public Health analyzes the scientific evidence supporting this “biomechanical” defense and concludes that:
“The biomechanical approach to injury causation in minimal damage crashes invariably results in vast underestimation of the actual risk of such crashes, and should be discontinued as it is a scientifically invalid practice.”
The authors abstracted, pooled and compared data from three categories of published literature:
- volunteer rear impact crash testing studies
- ADL studies
- observational studies of real-world rear impacts
They found that the average peak linear and angular acceleration forces observed in the head during rear impact crash tests were typically at least several times greater than the average forces observed during ADLs. Of even greater significance, the injury risk of real-world minimal damage rear impact crashes was estimated to be at least 2000 times greater than for any ADL.
This analysis demonstrates that the principle underlying this common defense in MIST cases – that occupant acceleration is a proxy for injury risk – is scientifically invalid. This article will likely be featured in future motions to exclude this misleading, unreliable, expert testimony.