The post formerly known as the Saturday Question

As I’ve no doubt demonstrated by now, the Saturday Question is a bit of a misnomer. With that in mind, I happily unveil the Weekly Question. Maybe it’ll be on a Sunday, maybe a Tuesday. Stay on your toes!

At any rate, this week’s question was submitted by Annoying Mouse:

Recently, there was a fatal collision in my area. I am puzzled over how the police were able to determine who was where etc. I know from the witness statements they would have the general idea, but how do You/motor officers prove those statements? What is the orange paint around the front tires for, how do you measure or whatever with all the fire truck traffic and cops cars going across the tire tracks? A very sad accident when an innocent person is killed. Or maybe if this question is too detailed you could explain the training for accident scene reconstruction, what you have to measure and why.


Annoying Mouse

There are a number of questions Annoying Mouse has asked. I’ll try to take them in order. First off, how we figure out who was where. We do take a number of witness statements. In my opinion, if you can get three to four independent witnesses that all more or less say the same thing, it can be fairly reliable. However, nothing is better than evidence. Evidence has no agenda, morality, point of view, or ability to lie. It simply is. Evidence will tell you exactly what happened…you just have to know what to look for and how to interpret it.
In some collisions, you can see a tire friction mark, or skid mark, leading to one tire or another. This may be able to give you a good idea where that particular vehicle came from. Not only that, but a measurement or two, plus some good old fashioned math, can determine how fast that car was going. (This is a simplified explanation, to be sure, but the theory is sound.)
The orange paint you may see around the tires notates the position of rest of the vehicle. At the scene, we will mark each tire and the center of same with the notation LR (left rear), RR (right rear), RF (right front), and LF (left front). The purpose of doing that is so when the tow trucks come and take the cars away, it’s still possible to have a good idea where the cars were. Ultimately, it’s best to shoot the scene (using Forensic Mapping equipment) while the cars are still there for more reliable accuracy. Sometimes, though, that is not possible. We do the best with what we have.
With regard to the Evidence Eradication Team (or Fire, if you prefer), we wait until they’ve come and gone to do the lion’s share of our evidence gathering. We shoot everything. Okay, not literally everything, but a lot of stuff. We shoot the basic structure of the intersection and/or roadway. We shoot the outlines of the vehicles at point of rest (if possible). If that is not possible, we’ll shoot them at the tow yard and put them on paper after the fact. This goes back to marking the tires. If we know where all four tires were at point of rest, we can put those vehicles back there later on paper. We shoot the tire friction marks. We shoot debris related to the crash. We shoot points of body evidence and/or bodies. (I went to a shoot once where we had over 80 different points of body evidence…it was a solo vehicle collision with one occupant. Looked like the car exploded).
Once we’ve shot the entire scene, we hook up the data collector from the Forensic Mapping equipment to a computer and download all the points. The program then literally draws the scene for us. Using that drawing, we can use some fairly involved math equations to determine speeds and, hopefully, fault.
Believe me when I tell you this is the Cliff’s Notes of the Reader’s Digest version of how the collision was investigated. I have completed over 400 (now 600+ as of 7/27/14) hours of Collision Investigation specific classes that I could not begin to do justice to in a post.
Hope that answered your questions, AM! Thanks for the question! I know you referenced some pictures and, originally, I posted them, but I was sent a message (appreciatively so) that posting pictures of a case that has not been adjudicated may present some issues…even though other news-related sites already have done so. I wouldn’t want my posting the pictures to create any issues for those involved in the investigation. And…just to assuage any curiosity…I was not nor am I involved in any aspect of the collision.
And that does it, folks, the inaugural Weekly Post. See? It’s Monday! Take that, Saturday!

Please note: I reserve the right to delete comments that are offensive or off-topic. Snark is encouraged. Being a prat is not.

9 thoughts on “The post formerly known as the Saturday Question

  1. As a trained reconstructionist I'll second MotorCop.

    After significant training you can look at this stuff and interpret it. You can tell from the damage on the cars how they impacted. Paint transfer and other damage point the way.

    The marks in the ground leave a lot of clues as well. You can often match specific damage on a vehicle to the marks it left in the pavement.

    Mathematical formulas based on physics and geometry can tell you how fast cars were going.

    Being on the scene of a major wreck with fatalities is like looking at a giant jigsaw puzzle. It can be difficult but the pieces do fit and you can put it together.

  2. Evidence eradication team. I like it. I think I'll get some t-shirts made and sell 'em at work. They will go well with our "Big County Fire Protection District – Conquerors of the Number 2 Lane" T-Shirts.

  3. Anon 1:40…

    Thx for the heads up. And seriously? You've never heard of the Evidence Eradication Team? That's just good 'ol wholesome ribbing, right there.

  4. "Evidence Eradication Team"!! My firefighters will love that.

    Having had a couple of reconstructionists in my life, that was a very good explanation of what they/you do. At least I could understand what YOU were talking about.☺

  5. The ad under this post reads "Is Your Man Gay?"
    Something you need to tell us, MC?

  6. No swearing? Is this a new trend? I didn't even notice!

    From what I understand, accident reports can be awful to fill out especially if it involves multiple accident victims or vehicles. My daughter's accident report was about 8 pages. I couldn't make heads or tails of it. Makes me appreciate what you have to go through when you respond to an accident.

    Thank you for taking the time to answer this question.

    Be safe.

  7. MC-

    I use Evidence Eradication Team…just not a phrase I like the general public to hear / read. Not a term I want thrown back in my face at a criminal / civil trial or deposition. I agree…the fire guys need a little ribbing every now and then. I'm still jealous…I haven't met a Soccer Mom yet who didn't like them…but as you know, Soccer Moms hate Motors. I like to use this quote on Soccer Moms when they get signed up. "If this is the worst thing that is going to happen to you today you should count your Blessings."

    Rubber side down, brother.
    -Anon 1:40

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