The OPP provided this photo on their Twitter account of a vehicle struck the unprotected end of a concrete barrier on Hwy 407 in Toronto.

If one only needed to draw conclusions about obvious matters collision reconstruction would be an easy process. Many reconstructions are generated in this fashion where an investigator only finds obvious things and nothing needs to be done beyond the obvious.

The photo shown above is taken from three photos provided by the OPP stemming from a seemingly simple incident where an impaired driver was travelling the wrong way on Hwy 407 and crashed into the unprotected end of a concrete barrier.

In one way the provision of such photos by the OPP is of great benefit. Independent persons  can provide comment on what is visible without being told what they must believe. Almost all police jurisdictions outside of the Greater Toronto Area (GTA) do not follow such helpful procedures and no photos are ever provided.

On the other hand the presentation of minimal photos to the public can create misunderstandings. Persons who are unfamiliar with collision evidence are allowed to make broad, unsubstantiated comments on social media, spreading all kinds of ridiculous conclusions. Even reconstructionists with many years of training cannot fully unravel what has been displayed in a few photos and much has to be assumed. It is why a proper reconstruction requires an examination of all the available evidence: Witness and driver statements, detailed examinations of the vehicles and collision site, and many other matters unique the incident at hand.

However the presentation of the photos in the present case can allow for some general comments and discussion about collision reconstruction in general. Before making those comments a viewing of the remaining two OPP photos needs to be made below.

The OPP officer who created and submitted these photos did a pretty good job. He/she provided a general view of the vehicle front end, a closer view of a spider-web fracture in the windshield and also provided a broad view of the vehicle interior. Considering that only three photos were provided, this was a good attempt by the officer. Along with the three photos the OPP provided the following comment on their Twitter account:

“Wrong way vehicle crashed into Barrier at #Hwy407/Mississauga Rd. Unbuckled 30 year old driver from Oakvile in custody at hospital with serious injuries. Arrested for #ImpairedDriving by #Highway407OPP.”

This is a very short summary, as if often the case in many police postings to the public. Much of what has been written must be assumed to be correct as independent verification can not be made from the minimal information in the three photos.

What can be observed from the first photo (of the vehicle front end) is that this was a moderate severity impact. We can make this comment by first considering that the concrete barrier is not crushable and dissipates minimal or no kinetic energy. So the kinetic energy existing in the vehicle upon impact must be represented in the visible crush on the vehicle’s front end.

As an aside, if the vehicle had struck a very large and soft pillow the vehicle might not exhibit any crush as all the kinetic energy might be dissipated by the crush of the pillow.  So, in this way, we can demonstrate that the extent of crush visible on the front end of the car does not explain everything. One must also look at what the vehicle struck.

Returning to our observations, the front end of the car shows that the left front wheel does not appear to be displaced rearward in its wheelwell. The grille area shows minimal deformation and the front edge of the hood is not deformed rearward. All these signs provide an indication of the moderate severity of the impact.

The second photo provides a view of the spiderweb pattern of fracture in the windshield. Traditionally such spider-web fractures are caused by the leading, forehead of an unrestrained driver. When such head impacts become more severe the occupant’s head becomes rotated such that the forehead moves backwards with respect to the face and the occupant’s face makes contact with the windshield glass. After the initial facial contact the face slides down along the fractured glass – not life-threatening but also not comfortable and resulting in substantial scarring of the face. So this is another reason why persons should wear seatbelts.

The third photo confirms that the air bag at the steering column has deployed. Note that the deployment has not prevented the driver’s head from striking the windshield. So for those who believe an air bag will save your life, that could be true. But an air bag has always been referred to as a “supplemental” device. In other words it supplements the primary protection provided by the seatbelt restraint system. So yes, the air bag may save your life but would you want to walk around for the rest of your life with major facial scars because you refused to wear a seatbelt? It’s your choice.

There are many aspects of this event that cannot be examined because of the lack of evidence. And here is the important point: we cannot always assume that the obvious occurred. Many investigators go through their lives documenting facts that are obvious to them while being unwilling to explore those rare instances where something obvious is not obvious. It is analogous to medical professionals who draw conclusions from obvious symptoms without probing deeper to eliminate unexpected, less-common causes. A good reconstructionist or medical professional will be one who is constantly on the alert to other possibilities except the obvious.

Using this example of the unrestrained driver in the barrier impact, in the vast majority of cases evidence such as this demonstrates the driver did not put on his/her seatbelt. But on rare occasions occupants can become unrestrained¬† because of a malfunction in the restraint system. It is rare but the possibility must be explored, even when the occupant was driving impaired. Event data recorders (EDRs) will provide an indication whether a seatbelt was buckled, but not always. In some instances when the data has not be written to a storage file the default value remains as “unbuckled”.

In many instances the investigator must become knowledgeable in interpreting physical evidence found on the seatbelt system itself. For many years I have documented seatbelt loading evidence resulting in patterns that could be used in interpreting, from the physical evidence, not only whether a seatbelt was worn but how it was worn. I have maintained this data for many years without much interest expressed in the investigative community. As a result many seatbelt usage interpretations have been made by investigators based on “obvious” facts; facts that are obvious to the investigator who often has little knowledge of the physical evidence existing on seatbelt restraint systems.

A good investigator, no matter in what realm, will learn from each incident or case they are examining. It is these previous facts that become the guiding light for the next investigation. It is this previous evidence that must be explained to new investigators. The unfortunate reality is that the vast majority of motor vehicle collisions where serious injuries and deaths occur crucial evidence is not documented and maintained in some form of database which can be used to understand what happens in future collisions and what can be done to prevent those future collisions.

UPDATE: March 5, 2022; 2105 hours

Subsequent to the posting of this article I was sidelined by surgical procedures and am slowly recovering. Lying in a bed allows for many thoughts to swirl back on recent events including this posting. Given this additional opportunity to comment I will say that nothing in this incident is simple and obvious such that my comments on the driver’s facial contact with the windshield should be treated with caution. Many years ago, when vehicles were not equipped with air bags, occupant facial impact of a windshield was very common in a frontal impact. I developed a special familiarity with comparing and differentiating between the fracture characteristics. But times have changed and so have vehicles. With the advent of air bags occupants do not reach head contact with the windshield like they used to. In fact many spider-web fractures are not caused by head contact but by a driver’s hand which is thrown from a steering wheel by the exploding air bag. But many of these spider-webs are of a smaller severity. The fracture in the present case is somewhat higher on that severity scale so the source of the fracture should be viewed as in doubt. And this is the additional comment I was hoping to make. If we had medical information on the occupant the source of the windshield fracture would be simple and “obvious” (that loaded word). It goes to show how proper reconstruction needs all the details and it is a dangerous proposition to reconstruct an incident with insufficient evidence.