Can you determine speed of vehicles from pictures?

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ambradley
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Can you determine speed of vehicles from pictures?

Post by ambradley »

This was a two vehicle accident that occurred during light rain so the ground was wet, as seen in the picture of the Ford. Unfortunately I don't have any pictures of the Infiniti at the scene of the accident. The pictures I have were taken a day or two later. The Infiniti's passenger side fender was dislodged from the body and left attached to the bumper cover. The airbags did not deploy and the windshield was not cracked. The body shop cut the fender off the bumper cover. The damage is otherwise as it was at the scene of the accident. It was only moved maybe 50 yards after the accident, as there was a body shop within one block, which is where the pictures were taken. I believe the Ford's rear bumper hooked into the Infiniti near the headlight assembly and moved forward (from passenger side to driver's side). As you can see from the Ford, its damage occurred behind the rear tire.

My question - can you approximate the speed of the two vehicles based on these pictures?
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Rusty Haight
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Re: Can you determine speed of vehicles from pictures?

Post by Rusty Haight »

ambradley wrote:(snip) My question - can you approximate the speed of the two vehicles based on these pictures?
No, not really. Damage (seen in the photos) would relate to the change of speed (delta-V) not THE speed over the ground. The weights of the involved vehicles and one of the vehicle's "delta-V's" and you can get to closing speed which, with information about how they came together (Angles, etc) and a known or assumed speed of one of the vehicles, would lead you to impact speeds. But damage itself is not about speed, it's about closing speed which relates to delta-V.
- Rusty Haight
Collision Safety Institute

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ambradley
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Re: Can you determine speed of vehicles from pictures?

Post by ambradley »

Rusty,

Thank you very much for the reply. I looked up delta-V to see what it meant, as I'm a complete layman. :-) I realize that I probably can't provide enough information to make an accurate assessment of the situation, but here's what I believe.

I'd estimate the angle was around 75-80 degrees (Infiniti on left, Ford on right, both approaching each other), as I believe the Ford turned to the right a bit to try to avoid the accident. I honestly don't think either vehicle's trajectory was altered by more than a few degrees. There was a minor amount of left to right car motion but my trajectory wasn't changed significantly if at all. I heard a honk shortly before the accident, which caused me to slow down. I really was going no more than 10-15MPH.

The curb weight of a 2006 Infiniti M35 is 3,832 lbs. I was in it, as was some fuel (about 1/4 tank - 5 gallons), a backpack - probably no more than 250 lbs total. The weight of a 1995 Ford Explorer is 4,242 lbs. I'd estimate the driver's weight at 150. I don't know what else might have been inside.
I realize this is just my guesstimating based on my memory of an event that occurred five months ago.

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