Calculate speed of vehicle vs distance of pedestrian traveled

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SUMMARY

The discussion focuses on calculating the speed of a vehicle based on the distance a pedestrian was thrown during an accident. Key factors include the vehicle's weight (4986 LB), pedestrian weight (320 LB), distance traveled by the pedestrian (90 ft), height difference (15 ft), and gravitational acceleration (9.81 m/s²). The conversation emphasizes the importance of employing a professional crash-scene investigator and references specific resources for pedestrian collision analysis. The need for accurate calculations and consideration of external forces is highlighted as critical for a reliable outcome.

PREREQUISITES
  • Understanding of physics principles, particularly kinematics
  • Familiarity with vehicle dynamics and pedestrian impact analysis
  • Knowledge of gravitational effects on motion
  • Access to professional accident reconstruction tools and methodologies
NEXT STEPS
  • Research the formulas for calculating impact speed using pedestrian throw distance
  • Study the methodologies outlined in the "Pedestrian Collision Investigators Guide"
  • Explore professional crash-scene investigation techniques and tools
  • Learn about the effects of external forces on pedestrian throw dynamics
USEFUL FOR

This discussion is beneficial for accident reconstruction professionals, traffic safety analysts, and legal experts involved in vehicular collision cases. It is also relevant for anyone interested in understanding the physics of pedestrian impacts and vehicle dynamics.

zippyconch
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I would like to calculate the above. Here are the factors. This has real life repercussions, and if further variables are required I will provide them if possible.

Vehicle weight (x=4986LB) includes 120LB driver, plus 50lb child and 60lb child
Pedestrian weight (p=320LB)
speed of vehicle (v=?)
distance p traveled (d=90ft)
difference in height (h=15ft) lower than impact because impact was on a hill and p landed in ditch
time (t=?)
acceleration (a=?)
gravity (g=9.81m/s squared)

please include formula/s used and how they applied. Thanks in advance.
 
Last edited:
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It sounds like you are trying to make a case for something in real life.
This is not a good forum to do this in.

Since this is important, you should employ a professional crash-scene or scene-of-accident investigator.

Aside:
You appear to want to know how fast a vehicle was going from the distance a pedestrian was thrown.
Typical approaches include:
http://jneades.com/downloads/Pedestrian%20throw.pdf
http://autoaccidentreconstructionguide.com/pedestrian-collision-investigators-guide-in-investigating-pedestrian-collisions/
... care has to be taken with these as there may be forces acting other than the impact and gravity.
 
Last edited by a moderator:
You are correct, and I agree this may not be the best place, and I apologize for that. Perhaps there is a "good" place somewhere, I just haven't found it yet.

The investigation is over as far as they are concerned, and they did not complete certain areas of investigation, like indicated above. This is why I am here.

You have given me a few leads, I will do my best with that. Thanks.
 

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