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In addition to the collection of physical evidence, a thorough investigation of a highway crash event generally includes interviews with available drivers, passengers and witnesses. These statements are often in conflict and inconsistent with the physical evidence. Driver statements are particularly suspect since they are likely to be untrue, or at least self-serving. Some common examples that I have heard are:

  • “The other vehicle came out of nowhere.” (Maybe because you were not looking?)
  • “She hit me. I did not hit her.” (But you ran the stop sign.)
  • “He hit me so hard he had to have been speeding.” (Wishful thinking?)
  • “I only had two drinks.” (How big were they?)

Witness statements are usually honest, but experienced investigators and reconstruction analysts, including myself, agree that they are generally unreliable. Research studies by psychologists and behavioral scientists have shown that witness accounts of any event are, for various reasons, likely not to be credible. Highway accident research has also confirmed that witnesses to a collision should not be considered reliable sources of evidence.

An actual witness to a collision may have a clear view, but may still confuse the sequence of accident events, place the vehicles in the wrong lanes, recall the status of the traffic signal incorrectly, and/or estimate vehicle speeds based upon the noise of the impact or their personal assessment of the damage. My experience indicates that most people, including witnesses, judges and jurors, substantially overestimate speed based upon vehicle damage.

Often witnesses, observing only a small portion of an accident sequence, will, in their own minds, quickly reconstruct what they think must have happened and report this as actual observations. Someone who only saw the aftermath of a crash (tire marks, debris and damaged vehicles) may give a similar statement. From this evidence they will perform their own reconstruction and assume this is what happened. Since most people are experienced drivers, they think they are experts and actually believe their assumptions are valid.

Another common problem arises when police, insurance adjustors, or private investigators elicit answers that agree with their preconceptions or desired testimony. This practice can usually be identified by the use of leading questions, such as “Did you stop before turning on red?” Although it is obvious that witness statements must never be the basis for any reconstruction conclusion, they should receive serious attention since they can raise issues that require another look at the physical evidence or consideration of additional factors related to accident causation.

The following case is an interesting example of an erroneous statement by a driver that actually proved to be useful. It was raining and a woman braked hard in an attempt to avoid a left-turning vehicle. She stated that while braking her car suddenly speeded up and collided with the other vehicle. An inspection of her car revealed no evidence of brake failure or unwanted acceleration. After some thought, this led to a careful examination of the roadway geometry. A significant depression was found in the pavement where water would have collected. This pool of water had actually caused hydroplaning. The cause of the accident was a highway defect and not a vehicle problem. In view of this finding her testimony made sense. While braking she was experiencing a significant deceleration that would cause her to brace herself on the steering wheel to prevent a forward movement. Upon entering the pool and hydroplaning the magnitude of the deceleration was reduced to near zero, thus causing her body to move rearward, releasing pressure on her arms. This positive change in acceleration would create the same sensation for the driver as a sudden acceleration. I learned an important lesson. Do not discount apparently ridiculous statements before giving them careful consideration.

More information on related topics can be found in Highway Accidents: Investigation, Reconstruction and Causation available at: Information about the book and author is available at: