The Traffic Accident Reconstruction Origin -Approach Angles-

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This is TARO Approach Angles. It a place for traffic accident reconstructionists to compare ideas, notes and methods of solutions. Rarely does a reconstructionist have all the information he wants. He must make assumptions about the collision to arrive at an answer. You are invited to examine the facts about the accidents below, decide on an approach, write up a solution and submit your answer. Approach Angles will publish the submissions of several different reconstructionists. Each solution will represent a different analysis of the same set of facts.

This is also a place to learn. There are many schooled reconstructionists that don't have the benefit of hundreds of collisions to draw upon. When given all the "numbers" they can do the calculator part and arrive at the correct answer. But the numbers are not printed on the road, the damaged vehicle or the skidmark. The evidence has to be recognized as important, documented and then measured. After all the facts are gathered, it's time for the calculator. The solutions published here are an opportunity for the schooled but lesser experienced to learn. It's a chance to look over somebody else's shoulder.

• At the bottom of this page are the details of several different collisions. Click on the title to read the description of the accident.
• If there is a critical fact missing you must make an assumption.
• Review the facts. Look at the evidence. Crunch the numbers. Then submit your answer.

Guidelines for submissions.

Your report should be a narrative of:

• What were the important questions about this collision? (Clearly, the central question in this collision is the speed of the truck. The view obstruction ...)
• What evidence was relevant to your analysis? (The rest location of the pickup truck is crucial to ... This skidmark means...)
• What additional evidence would you have looked for if you had access to the cars, the witnesses or the accident scene? (Given the opportunity I would have measured ... This would have allowed...)
• Explain any contradictions found in the evidence. (The witness statement is disputed by the physical evidence. This contradiction is resolved by...)
• How did you choose the values for the unknowns in your calculations? (The ... was unavailable. Test published in the Nov-Dec 94 Accident Reconstruction Journal indicate an appropriate range for this ... The ... was measured from the scale diagram.)
• What general analytical method did you use for your calculations? (A momentum approach to the evidence... The damage to the vehicles leads to...)
• What problems prevented you from using a particular type of analysis? (Momentum would have been used if...)
• Include any software you used. (Given the ... input, the program CRASH-43 yields an answer of...)
• Include any working drawings you needed (Vector diagrams, photogrammetry... [Be neat as they will be scanned just as you submit them]).
• Include all the variables and submit your numbers . (With approach and departure angles of ... The post collision speed is calculated with a drag factor and distance of ...)
• State how accurate your speed estimate is. (The speed of the truck was 48 M/H plus or minus ...)
• Try to make your reasoning explicit. (The pre-collision skidmark means the driver had his foot firmly on the brake which in turn means he was not asleep as he says. From this we can then infer...)
• Draw a definite conclusion. (If the truck had been going the speed limit...)

How to Submit a Solution

If there is already a solution published that is similar to the one you would take, there is no need to duplicate it. In order to prevent duplication of work contact TARO ( feedback or a phone call) prior to committing to your analysis.

The suggestions for the narrative are exactly that: suggestions. If they are not appropriate ignore them. Feel free to use your own particular reporting style. But, remember your audience as you write. You don't have to explain what a skidmark is.

Software authors are welcome to submit your products analysis of these facts.

Most importantly, if you disagree with a published solution, assumption or technique, document your position and submit it. That is why Approach Angles is here.

1. a printed copy of your analysis.
2. 8.5 x 11 hard copies of all exhibits (software reports ...).
3. a 3.5 inch floppy disk with:
• an ASCII file of your narrative.
• any CAD files in a DXF format.
• any graphics you generate as .GIF file.
4. drawings or photographs you used (sketches, a photo of an exemplar vehicle ...).
5. a longhand calculation sheet. (it will be scanned as a graphic).
6. anything else you think important.

TARO Approach Angles
PO Box 6200
Lake Worth FL.
33466-6200

A word about the information presented here.

These are descriptions, pictures and diagrams of an actual collision. This information is drawn from documents that are in the public record. TARO recognizes that a serious collision has deep personal consequences to those involved. The display of this information is not an attempt to draw attention to any person, or add to the difficulty or loss that they face. Rather, these facts are presented so that others might learn from their misfortune. It is the hope that future collision victims will benefit from this analysis with a more accurate investigations and safer vehicles.

Taro will deliberately disguise the names of individuals, tag numbers, street names, facial features and any other information that might bring attention to those persons involved. These changes will not affect the material facts and their subsequent analysis.

A List of Cases

 A rainy day collision Solutions Smokeout Solutions Too Fast Solutions Ped Skid Solutions An Errant Piece of Evidence Solutions Motorcycle Photo Solutions Tire Marks Solutions Why do we pull drag sleds through the center of mass? Solutions What is Context? Solutions Two Inline Momentum Problems Solutions Two Different Stories Solutions Two Green Lights Solutions No Announced Solutions Speed Estimate From Crush Solutions A Solution by Jim Mitchell No Announced Solutions

If you have a case you would like to present here, outline it and E-mail it to TARO through feedback.

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