Mathmaticians/ accident reconstructers

[wolfie]

A friend/coworker crashed his motorcycle Fri. He now has no recollection of any of the past year including the accident. Otherwise he is hurt but will heal so we count our blessings. I looked at the accident site yesterday and would like to calculate how fast he was running. I am not finding a formula online though I would believe there is one. He slid 8-10 feet on the rear tire (presumed braking skid) before the bike was down on its right side and sliding on the shock and front crash bar. The bike (Harley Sportster) then slid, remaining on the asphalt in a straight centered in the lane slide, for 65'-70' more. He (his body) went into the grass 10-15 feet from where the bike initially landed and slid near 50' total at about a 25 degree angle digging 2 furrows about 4" deep in the grass part of his slide. He was climbing a hill with approx 30 degree incline. Was he flying or is that about expected? There are lots of questions about why he went down and hit the way he did and how everything was handled immediately afterward. MIGHT have been a car involved (first reports) but no indication of any impact with a car. I do question why he put the bike down , especially on the right side, in that short of a slide if he wasnt dodging something but have had enough motorcycle crashes to know stuff happens fast and especially if you are riding on the edge of your abilities. Thanks, Steve

[8E45E]

Contact these guys: http://www.scarsrecon.org/

(and ASAP before other traffic and rain removes any fresh evidence/clues)

Craig

[Swifster]

Did you look at the speedometer? A lot of times the speedometer freezes at impact.

[wolfie]

Contact these guys: http://www.scarsrecon.org/

(and ASAP before other traffic and rain removes any fresh evidence/clues)

Craig

Thanks, But there are a few issues. Mostly, this guy has no money, insurance, or even steady work. Folks immediately onsite loaded him up before he came to and hauled him away to the hospital. Others (family) took the bike to his mothers house nearby. No accident reports, ambulance reports, etc... The crash scene has already been cleaned of any debris (not even any glass from the broken mirror or a reflector that was torn off) and there are no signs on the bike at all that it contacted anything except the asphalt. There are a number of scenerios that could, maybe, involve a car or someone in a car may have simply been the first person to arrive, if in fact there was ever even a car there. There are at least an equal number of scenerios that would involve a deer, dog, bird, etc.. or, sadly, he could have made a stupid decision and got on the bike hard showing his butt and let it get wilder than he could recover it from. Steve

[wolfie]

Did you look at the speedometer? A lot of times the speedometer freezes at impact.

Yep, sitting dead on zero. The bike slid hard but really isnt hurt badly at all. They rode it back to his mothers house. Steve

[Don Jeffers]

A friend/coworker crashed his motorcycle Fri. He now has no recollection of any of the past year including the accident. Otherwise he is hurt but will heal so we count our blessings. I looked at the accident site yesterday and would like to calculate how fast he was running. I am not finding a formula online though I would believe there is one.

Some good data:
He slid 8-10 feet on the rear tire (presumed braking skid) before the bike was down on its right side and sliding on the shock and front crash bar. The bike (Harley Sportster) then slid, remaining on the asphalt in a straight centered in the lane slide, for 65'-70' more. He (his body) went into the grass 10-15 feet from where the bike initially landed (stopped?) and slid near 50' total at about a 25 degree angle digging 2 furrows about 4" deep in the grass part of his slide.

Some questionable data:
He was climbing a hill with approx 30 degree incline.
This angle is critical to an accurate solution. Hardly no way was there a 30 degree incline on a paved road. PM me and I will guide you through how to get an accurate measurement.

Was he flying or is that about expected? There are lots of questions about why he went down and hit the way he did and how everything was handled immediately afterward. MIGHT have been a car involved (first reports) but no indication of any impact with a car. I do question why he put the bike down , especially on the right side, in that short of a slide if he wasnt dodging something but have had enough motorcycle crashes to know stuff happens fast and especially if you are riding on the edge of your abilities. Thanks, Steve

Putting the bike down is a good way to avoid a fatal collision with a vehicle, unless you go under something like a guard rail or another vehicle. Odds are it was a good move.


This problem will be solved in two or three parts with the correct data.


Don

Contact me.

[wolfie]

Contact me.

Don, PM sent.