Often the public is incapable of interpreting collision evidence that leads them down an erroneous path.

The internet is full of experts who use false information to confuse, and sometime defraud the public. The realm of collision analysis is no exception. A common theme is to use false evidence to support a false claim. There are many examples where collision evidence is misinterpreted, sometimes on purpose. The classic case is one of using the existence of collision damage as an indicator of collision severity and vehicle speed.

The above photo was posted on the Boston Fire Department Twitter account showing a recent impact of a building at Corinth St. Roslindale. The massive destruction of the building caused many viewers to be amazed that a car could cause so much damage. This naturally leads to the belief that damage must equate to massive severity of impact and an incredibly high speed of the vehicle. It only requires a quick look into the debris to observe that the front end of the car shows little in the way of rearward crush. For example the right front fender appears to be relatively undamaged. There is damage to the windshield and roof of the vehicle but that is mainly due to the debris falling down from the fa├žade of the building.

There is a simple relationship involved here that Sir Issac Newton encapsulated centuries ago: For every action there is an equal and opposite reaction. In short, in an impact of two objects, the force applied to one partner must be equal to the force applied to the other partner. In the above example of the building collapse the force applied to the building must be equal to the force applied to the car. When we see the obvious evidence of major damage to an object we do not know the object’s properties. A building may be very strong in terms of holding itself upright but it may be brittle and may not be able to withstand the vibrations of a lateral force. The evaluation must involve the examination of the collision partner, the car, to determine the magnitude of the force that was involved.

In the world of motor vehicle collision reconstruction we know quite a lot about the structural properties of motor vehicles. For example Federal Transportation agencies routinely collide vehicles into immovable barriers. And with the advent of event data recorders (“Black Boxes”) there is a lot of data that allows comparison between visible damage, change-in-velocity and acceleration. So in the above case, even without detailed data, we can look at the damage to the car to see if it supports our belief that the building sustained a tremendous impact.

Clearly, even from this very cursory view, the damage to the building does not match the relatively mild damage to the car. The damage to the building is likely the result of the gravitational force, the normal force, which collapsed the building when the foundation of the bricks. etc, was disturbed. Yet, to the inexperienced eye, all it needs is some “expert” to fool the general public into thinking this must involve a vehicle travelling at a tremendously high speed. This is just one example where the public is continually fooled into believing all sorts of delusions by persons willing to take it down that delusional path. The internet has provided the means by which millions of viewers can receive the same delusional message and be influenced by it.

The moral of the story: buyer beware. The public must be better at critically evaluating what it is swallowing.