Are there photos showing damage and patterns for different type of collisions?

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wfz
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Are there photos showing damage and patterns for different type of collisions?

Post by wfz »

I encountered a situation that the offender claimed that both skid and hit each other in the middle of a 2 lane highway while in fact it was him hitting me at the right lane while switching lanes without looking. I wonder if there is a general pattern for each situation that you can tell that which one is true by looking at the damage photos?

Thanks for your help,

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actar670
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Re: Are there photos showing damage and patterns for different type of collision

Post by actar670 »

In general, damage can be used to determine the angle at which two vehicles collide with one another. The damage profiles are then compared to the tire marks on the highway to determine how the two vehicles interacted with one another.

I'm sorry I cannot give you an answer about what damage profiles to expect in the two scenarios you've given, since the described circumstances could result in a number of damage profiles for the two vehicles, depending the angle of impact, area of contact on each vehicle and the relative speed of each vehicle.
Bruce McNally
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41 Champlin Ridge Road
Rochester, NH 03867
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Re: Are there photos showing damage and patterns for different type of collision

Post by sd3225 »

This is one of those questions that needs more information to maybe be able to help you. It could have different answers depending on the dynamics. If you have some photos and can clarify some details, such as in a simple sketch, it may be easier to give you an idea on what damage pattern I would expect to see in that collision. Collisions are a "puzzle" in which all the pieces must fit together reasonably well. By that, I mean the type and direction of damage patterns must match what the vehicles where doing as evidenced by roadway markings, witness statements etc. I know that's kinda vague, but I hope it helps some

Doug
JDEAssoc@gmail.com

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Re: Are there photos showing damage and patterns for different type of collision

Post by wfz »

Thanks for the info. I am including the picture of the car and my analysis of what I think can prove that I'm not the party to blame.
020519_44.jpg
Accident.jpg
My main arguments are:
The wheel of the truck left multiple circular lines on the side of car. It is more in line with sideswipe pattern than swerving into the middle of 2 lanes. How likely was it for 2 vehicles to have that pattern if they swerved to hit each other? The only minor damage to the truck was the right front wheel.

There was an extruded object in the center of the wheel. That object left a long straight line moving up toward the end before leaving the car. I think the difference in height was caused by fact that the wheel had to take the path of least resistance after hitting the car. If it's the reverse or more hitting each other, it's more likely to be of the same height from the beginning to the end. Does that make sense?

There is a big difference in speed between the 2 vehicles. I traveled at 62mph while the there was a clear line of 34 inches in front of the impact point showing that the truck traveled at faster speed before leaving my car. Based on info found on internet, the average time of impact is 0.1 to 0.2 seconds. I used 0.2 for calculation, 34 inches is roughly = 10 MPH faster in speed. If it's really as what he said that the traffic slowed down that we both braked and swerved to hit each other, how can there be such a big difference in speed. If we hit each other at that speed in the middle of the 2-lane major interstate highway, I double it could be just a minor accident like that. The car behind would have hit us and I probably won't be alive to tell the story.

Although I'm 100% sure I wasn't the one at fault, I wonder if I can find more proof (such as past data) to support my analysis. How likely to win the case if I have to go to court?

Thanks for the help,

wfz
Last edited by actar670 on Mon Jun 04, 2012 6:08 am, edited 1 time in total.
Reason: embedded the photos and added spacing to paragraphs.

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Re: Are there photos showing damage and patterns for different type of collision

Post by actar670 »

I would be interested in seeing a photograph or two from the pickup involved in the crash, but the photograph of your vehicle shows a lot about the manner of contact between the vehicles. The damage to the left side of your vehicle is consistent with a sideswipe contact with the right front tire of the pickup. The uniformity between the circumferential marks made by the front half and the rear half of the tire indicates that the tire was approximately flush with the side of the car during contact, suggesting a very shallow angle of impact.

Of primary significance is that the damage on the car travels from front-to-rear along the left side of the vehicle. The point of maximum engagement is at the left B-pillar, where the wheel/rim from the pickup snagged the leading edge of the left rear door panel and displaced it rearward. The manner in which you have attempted to calculate the speed of the pickup is simply wrong. One cannot simply pull a "time of impact" number out of the air and try to use that in a time-distance calculation as you have attempted here. In sideswipe impacts, the time the vehicles are in contact with one another can be significantly longer than in a "full" impact, where the .1 to .2 second impulse duration might be a more justified.

In the diagram photo you posted, you discuss your theory of how the contact to the right front tire might have caused the wheel to lift up some 3.5 inches as the contact progressed along the vehicle. However, this theory includes the false premise that the pickup was traveling faster than your vehicle. Because the damage travels from front-to-rear along the side of the vehicle, you need to think about what was happening to your vehicle at the time of the crash. The reason that the front of the mark is higher from the ground than the back of the mark is because your vehicle was being braked heavily at the time of impact. The heavy braking caused weight shift, forcing the nose of the vehicle toward the pavement and lifting the rear of the vehicle upward.

With what you have shown thus far, I don't believe there is sufficient evidence to conclude which vehicle was straying out their travel lane at the time of impact. As I suggested in my first post, you should compare what you have for vehicle evidence to the tire mark evidence at the scene. With a heavy tire contact such as that seen on the B-pillar of your car, there should be a nice tire scuff on the pavement showing the position of the right front tire of the pickup at the moment of maximum engagement. That should help solve where the vehicles were positioned at the moment of impact.
Bruce McNally
McNally & Associates ARS, LLC
41 Champlin Ridge Road
Rochester, NH 03867
Office (603) 516-4560
Web http://mcnallyassociates.com

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Re: Are there photos showing damage and patterns for different type of collision

Post by wfz »

> I would be interested in seeing a photograph or two from the pickup involved in the crash
I didn't take any picture. From what I remember, there was no visible damage except the wheel especailly the center piece of ~1" in diameter.

> As I suggested in my first post, you should compare what you have for vehicle evidence to the tire mark evidence at the scene.
I went back to the scene (general area) and didn't see any mark. How long can the tire mark last? This happened just over 1 month ago. From what I remember, I didn't brake much as I was afraid of losing control. All I was thinking was to move out of the path as much as I could without losing control. Unfortunately, the distance was too short for me to get away. If you believe it definitely wil leave marks, I will drive back and park the car to look.

> In sideswipe impacts, the time the vehicles are in contact with one another can be significantly longer than in a "full" impact, where the .1 to .2 second impulse duration might be a more justified.
I was wondering about that too. Most articles were about head-on crashes. How can you calcuate the speed in this case? At least the photo can tell you that the truck is traveling at fast speed than my car or line would be formed after the impact point, right?

From what you're saying, it's almost no hope of getting enough evidence without the tire mark.

Thanks for the help!

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Re: Are there photos showing damage and patterns for different type of collision

Post by actar670 »

The tire mark evidence on the roadway I mentioned would be from the right front tire of the pickup at the moment it locked up at the point of maximum engagement with the B-pillar on your vehicle. This tire scuff would not be expected to last long, especially on a high-traffic roadway. If you didn't find a scuff mark when you went out initially, don't expect there to be one after a month of traffic traveling over it.

With the information you have available at this point, there is no way to independently calculate a speed for either vehicle at the moment of impact. A trained reconstructionist may be able to calculate a relative speed between the two vehicles based upon the striation pattern left during the tire contact. One cannot calculate a speed based upon the damage profile on your vehicle, but a trained reconstructionist could reasonably estimate the probable speed change experienced by both vehicles as a result of the collision.

Lastly, maybe my previous post was not clear, but the physical evidence clearly shows that your vehicle was traveling faster than the pickup at the moment of impact. That is why the initial contact on your vehicle is on the forward half of the left front door and the point of maximum engagement is on the B-pillar.
Bruce McNally
McNally & Associates ARS, LLC
41 Champlin Ridge Road
Rochester, NH 03867
Office (603) 516-4560
Web http://mcnallyassociates.com

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Re: Are there photos showing damage and patterns for different type of collision

Post by Dwight »

I would have to concur with Bruce on this... I had this happen to myself. I was driving an MG in the right hand land of a two lane road heading north, as I was passing an armoured truck (money delivery) he moved towards my lane. My driver door at that point was beside his front passenger tire and we made contact before I could evacuate the lane. The marks on my door are very much like the ones you show. The curve marks cut by the spinning lug nuts cut deeper toward the back indicating I was traveling faster, which I was... I was trying to pass his vehicle.
Dwight Magee

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Re: Are there photos showing damage and patterns for different type of collision

Post by wade_b »

You might want to check out these publications, I have my own ideas of which are most useful, but you should be aware of each of them.
"Forensic Evaluation of Relative Sideswipe Speeds", Bartlett and Hochgraf, Proceedings, CMRCS XI; Halifax Nova Scotia, Canada, May 1999
"Modelling of Truck-Car Sideswipe Collisions Using Lug Patterns", Varat, Husher, Kerkhoff, Armstrong, SAE 2008-01-0179
"Speed determination in car-truck sideswipe collisions", Levy, SAE 2000-01-0463
**************************
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Re: Are there photos showing damage and patterns for different type of collision

Post by wfz »

Thank you all for the reply. Sorry I misunderstood. So you're saying the line was formed when the truck initially contacted my car before reaching the maximum impact at B-pillar. Is that what usually shows up in a sideswipe accident? What evidence does it tell you it's the reverse. It might be true that I was faster. It happened that left lane suddently get congested while there was a long distnace between the vehicle ahead of me and my vehicle. This truck just switched lane in front of me (felt like at 11 o'clock position from me) that I couldn't move right away from the truck in a short period of time. Since he got slowed down while I didn't (usulally traffic is slower at the right lane), so the speed of the truck could be slower than mine.
He told his insurance company that traffic caused both of us to brake. He swerved to the right while I swerved to the left that both vehicles collided in the middle. If I were to not the hit the vehicle ahead of me, why would I turn left instead of turning right to the shoulder? If both car swerved to the middle, the marks on my vehicle and the damage to his vehicle should show a sharp angle. Based on the picture above, do you see any possibility that it could be happened the way he discribed (instead of trying to prove he switched lane to mine, prove that he said was impossible)?

> The reason that the front of the mark is higher from the ground than the back of the mark is because your vehicle was being braked heavily at the time of impact. The heavy braking caused weight shift, forcing the nose of the vehicle toward the pavement and lifting the rear of the vehicle upward.

I don't recall I braked, but might have braked subconsciously. All I remember was that I tried to move away from the truck. Is this the only explanation for the angled line?

Thanks again for your information,

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Re: Are there photos showing damage and patterns for different type of collision

Post by wfz »

wade_b wrote:You might want to check out these publications, I have my own ideas of which are most useful, but you should be aware of each of them.
"Forensic Evaluation of Relative Sideswipe Speeds", Bartlett and Hochgraf, Proceedings, CMRCS XI; Halifax Nova Scotia, Canada, May 1999
"Modelling of Truck-Car Sideswipe Collisions Using Lug Patterns", Varat, Husher, Kerkhoff, Armstrong, SAE 2008-01-0179
"Speed determination in car-truck sideswipe collisions", Levy, SAE 2000-01-0463
I can't find any of them on web. Can you provide the link? THANKS!

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