The Collision Reconstruction Matrix – The Human


Expertise Includes:

    • Tractor Trailer Accidents
    • Vehicle Collision Reconstruction
    • Crash Data Retrieval
    • Forensic Mapping Technology
    • Accident Investigation
    • Accident Reconstruction
    • 3D Scan Imaging

Murder, suicide, deceit, and intrigue… car crashes? You bet! In our next installment of the 9-Cell Collision Matrix let us dive a little deeper into the glue that binds all this together, the human element.

Photo by Mark Turner

Let’s begin with the most basic human element at the root cause of car wrecks, our old friend inattention. Inattention… a vast word that encompasses many lackadaisical conditions. The daydreaming 16-year-old in math class, the radio knob turner, the back seat talker, the quarter pounder with cheese eater, and perhaps the most offensive, the cell phone user. All very dangerous behind the wheel, and one very dangerous to your future… as it turns out, you will always need good math skills… ask me how I know? Driving is of course a divided attention endeavor, but one of those divisions must always be an unwavering attention to your surroundings or bad things will eventually happen. Consider please, for a second, these numbers. If a person is traveling at an average highway speed of 70 miles per hour, or almost 103 feet per second, coupled with an inattention period, you name the malady, of just 3 seconds… that person has now just traveled the length of a football field without knowing anything about what’s around or in front of them. Scary stuff!

Intoxication is a whole other animal altogether and worthy of its own place in print, but now imagine a level of intoxication mixed with one of the above factors… or just plain old fashion tiredness… it starts to stagger the mind as to how dangerous driving everyday really is.

Could the cause of a deadly car wreck be more than an accident? If so, can that be empirically confirmed? Yes, and maybe. Car wrecks are often intentional… Murder? Suicide? Murder/Suicide? Insurance fraud? What about a staged wreck to cover up a murder that occurred elsewhere?… Yes! But how can we prove it? Ah, therein lies the rub. Proof of these difficult situations means different things to different people according to their involvement level. From an investigative standpoint, things like our old friend the EDR, remember this guy from the last blog, can give some interesting data. I’ll give you an example; A 2021 Chevy pickup with a 38-year-old male driver strikes a tree, head-on, off the right side of a rural road. The male driver of the pickup sustains fatal injuries as a result of the crash. An imaging of the EDR data reveals that the pickup driver was unbuckled and accelerated to the maximum throttle percentage with a steering angle change that would have drove the vehicle off the right side of the roadway… all this was recorded with the last three seconds of EDR data after having normal driving readings for the first two seconds. Can we prove intentionality with the EDR alone? I’m good with it, but more would most certainly be needed.  A couple of days later you find out later that the male driver was fired from his job two hours before the wreck and that his wife had filed for divorce last week due to his alcohol abuse. Are the collision events starting to make more sense now?  The county coroner states that he didn’t leave a note and the family says that he would never do that. Does that sway your opinion? Mine neither! This example is certainly a sad situation, but an all too real and often overlooked, sometimes purposely, reality in car wrecks.

Photo by Mark Turner

By and large when we speak of human factors as they relate to car crashes, it revolves around the nucleus of past experiences, or having seen this before, but it also goes much deeper.

Driver perception, recognition, and understanding of the true character of a hazard or potential hazard and the time it takes that individual driver to respond is a scientific study all its own, laced with many factors. Is it day or night? Clear or raining? What is the drivers age or health condition? What kind of collision is it… perhaps a path intrusion coming from left to right within the confines of an intersection? Or a lane intrusion from a vehicle coming head-on?

A very common wreck that involves an abundance of human factors is the left turning tractor trailer at an intersecting roadway. As the tractor trailer enters an adjoining roadway and starts the process of completing the left turn, it will inevitably take up both lanes of travel. This often results in the tractor being located in the proper lane of travel, leaving the trailer blocking the lane of any oncoming traffic. As the oncoming traffic approaches, what do they see? Headlights in the opposite lane? Okay… check! When you drive on a two-lane road at night, what do you expect to see? Headlights coming toward you in the opposite lane? Sure… the brain connects those dots, right? Why? Because we have seen that a million times and those are the rules of the road. Faced with this exact scenario, would you then think the driver of an oncoming vehicle in any way expects a 48-foot trailer to be across their lane? I can tell you unequivocally, they don’t. Most of the time they never apply the brakes or if they do, it’s at the very last second. But doesn’t the trailer have marker lights on the side, and reflective tape? Yep! Then why? Because… how many times have you been driving down the road and had a steel wall fall from the sky in front of you? That’s what it’s like. Is it a conspicuity issue? It can be to some degree, but not really… I think a lot of time the drivers do see something; they just don’t recognize what they see as being a hazard until it’s too late to form a response.

Looming… an old problem with a new name! What would you say the chances of a broken-down car, stopped in the middle of the interstate, are of being struck? Yep… you’re right… 100%

What if I said it was on a flat section of the interstate on a blue bird day around noon… yep… 100%. What about a car having engine problems or an 80-year-old man traveling at 25 miles per hour on the interstate? Trust me, bad things are going to happen. But why? Aren’t they visible? Absolutely! Didn’t the person that hit them, see them? Absolutely! Why then? Because remember how we talked about human factors in car crashes being largely based on the philosophy of been there done that? How fast do we think cars are going when we merge onto the interstate? Usually at least 70 or so… right? Maybe 80?… and that’s the black fly in your chardonnay! What if you see that car going 80 miles per hour, 100 yards in front of you? Only it’s not going 80, it’s going 20. Are you going to be able to perceive that slower moving vehicle and react without striking it in the rear? Maybe… but probably not. That’s looming and it happens a lot.

Photo by Mark Turner

Homework Time! Pop Quiz! Please put your books under your desk and get out a pencil and a piece of paper! Remember our wreck from my last blog on The Vehicle, where we were focusing on EDR data? If not, you can cheat and go back and read it.

So, we had one vehicle traveling north and one vehicle traveling south on a two-lane asphalt roadway. The driver of the northbound vehicle crossed the double yellow line causing a head-on crash, which resulted in the southbound driver sustaining fatal injuries. The northbound driver survived with serious injuries, and we had an independent witness traveling north that saw the wreck but was otherwise not involved.

Lucky for us, we also have a completely unbiased witness of sorts; in that we have EDR data from both vehicles. Remember our EDR tables, Vehicle #1 was traveling 37 miles per hour 5 seconds before impact. The driver of Vehicle #1 then applied the brakes at the 3 second data point and slowed to 23 miles per hour at the last recorded EDR data point, 1 second before impact. Vehicle #1 also experienced a -33.37 (pushed backwards) miles per hour change of velocity in a tenth of a second. Vehicle #2 was traveling 71 miles per hour 5 seconds before impact. The driver of Vehicle #2 then accelerated to 74 miles per hour .1 seconds before impact without ever applying the brakes.

Remember our faithful witness statement? The driver of Vehicle #1 had passed the witness at a high rate of speed, while the witness was traveling north at the posted speed limit. Then while attempting to pass the witness, Vehicle #1 struck Vehicle #2, head-on, in the southbound lane. Do we believe the witness? No! Doesn’t the EDR data eerily reflect the exact opposite? It sure does! And as always with EDR data, did the collision scene evidence correlate, not only the EDR data, but which vehicle was on the wrong side of the road? All day!!

What human elements played a role in this crash? A lying witness. A lying driver. A feeling of invincibility, with many levels of inattention. What about a complete lack of empathy for the loss of life… the driver of Vehicle #2 had none. The driver of Vehicle #2 even conspired with an old high school friend, who showed up after the wreck, to give a false witness statement. Remember this is the human before, during, and AFTER the crash. We humans are flawed, and those flaws sometimes show up, in full effect I might add, in vehicle collisions

In the next blog, we will wrap things up with a look at the environment, and how it plays a major role in car crashes… as they say, nature can be one tough mother!

Mark Turner, ACTAR #2368, is a vehicle collision reconstructionist with Warren. Prior to joining Warren, he worked for 25 years as a South Carolina Highway Patrol Trooper including 10 years as a Multi-Disciplinary Accident Investigation Team (M.A.I.T.) leader (corporal). Mark is accredited as a Traffic Accident Reconstructionist by The Accreditation Commission for Traffic Accident Reconstruction (ACTAR). He investigated in excess of 900 vehicle accidents and incidents as a trooper. Then, as a member of M.A.I.T. for 10 years, he was involved in over 1000 detailed investigations and collision reconstructions. Mark has testified multiple times in state courts and has been court qualified as an expert in accident investigation and collision reconstruction.  Mark is a member of the South Carolina Association of Reconstruction Specialists (SCARS), the International Association of Accident Reconstruction Specialists (IAARS), and the National Association of Professional Accident Reconstructionist (NAPARS). He completed the Law Enforcement Basic Program at the South Carolina Criminal Justice Academy in Columbia, South Carolina.

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