ACCIDENT RECONSTRUCTION BASICS
PHIL BUCKLEY
JUNE 27, 2019
KCMBA
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CLE OBJECTIVE
1. Assure you know what to expect from an AR expert
– What is involved?
– How the work is done?
– What tools are important?
– What results can be expected?
– What formats will the results be available in?
– Effective Data presentation
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YOU SHOULD EXPECT…
• BASIC: Has prior formal reports/deposition experience/trial experience/recommendations
• Training in analytics & scientific support
• Prior related experience
• Quick understanding of “your incident” character
• A general investigation plan
• Clear visualization ability
• A Degree of Certainty in Opinion
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Degree of Certainty in Opinion
• Starting point ranges 0% to << 100% unlikely if I am involved – There is a contest for a reason!
• Most likely explanation can be <50%
• More likely than not (>50%)
• Reasonable degree of probability
• High degree of probability
• Reasonable certainty
• Reasonable degree of engineering certainty
• Absolutely certain – probably not going to happen
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DEFINITIONS ARE IMPORTANT
• ACCIDENT CAN INFER “ACT OF GOD” – INCIDENT HELPS FOCUS THE SITUATION IN A NEUTRAL
WAY ALLOWING FOR OTHER OUTCOMES – CRASH OR COLLISION ARE OFTEN USED FOR VEHICLE
• RECONSTRUCTION INFERS THAT WHICH IS KNOWN IS INCOMPLETE OR POTENTIALLY WRONG – FOR SOME REASON(S) THERE IS (A) DISAGREEMENT
ABOUT WHAT HAPPENED
• BASICS INFERS THIS CAN BECOME COMPLICATED – WHAT IS YOUR FIRST CLUE THIS ACCIDENT IS COMPLEX? – WHAT CAN YOU EXPECT FROM A RECONSTRUCTION? – WHEN SHOULD YOU LOOK FOR IT?
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Controversy
CRASH WRECK INCIDENT
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YOUR FIRST CLUE…
• Equivocal issue(s)
• Multiple conflicting stories or views of what happened – Story
• What they saw, felt, heard, smelled, tasted
– View • Where this person saw it from
– Missing data becomes very important • AR fills in the blanks, reconciles the “facts”
• Correlation is the goal
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YOUR QUESTIONS!
• You provide the legal basis of the potential claims
• Your expert provides the technical basis
– But , may not know the legalese…
– Finds a lot of things interesting…
• You formulate the questions that need to be answered to support those claims
– Your well formed questions will allow the AR expert to be efficient and economical in support of your case.
• Sooner is better!
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YOUR QUESTIONS!
• You are best served when your questions are focused on your legal case position
• You should tell the expert what your legal position – Is, or…
– what you think it is, or…
– that you need information to focus the position
• 1,2,3 priority – direct energy to greatest benefit
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Weak vs Strong cases
• Your strong case may not need an expert – No loose ends
– No jury bias potential
– Clear easy visualization of the incident
– Better yet, supportive, available documentation from a formal authority such as Highway Patrol, city police, OSHA
• But you may still benefit from Visualization – A picture is still worth a 1000 words
– A video can be worth a 1000 pictures
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What if the case is weak?
• Weakness comes from multiple sources; – Just plain bad case
– Apparent facts don’t clearly support the case
– Absentee facts in need to be uncovered
• Bad—get out with least damage
• Apparent facts need foundation work
• Absentee facts need to be dug out – local video/ unregistered witnesses/ scene changes caused
by the incident/ poor or non-produced photography/ Poor investigation report/ Bias statements by officials/ vehicle recalls/ unknown unknowns/
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JPB
View from NORTH View from SOUTH
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What if the case is weak?
• YOU REALLY WANT TO KNOW THIS!
–No case whatsoever!
–Weak: Where is it weak?
–Mitigating factors and hidden data
–An expert can help you identify cliffhangers and loose rocks that might not have been apparent
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A LOT DEPENDS ON SKILL LEVEL Analytics and Scientific Support
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Hand Holds & Toe Holds
• Vehicle recall data base • Telephone records • Weather reports (Historical) • Sun Position and Effects • Commercial driver records • Black box downloads • Testing instruments (force, friction, pressure,
acceleration, speed, time, etc.) • Recognized standards (NHTSA, IIHS, SAE…) • Vehicle Specifications • Detailed first-hand inspections and testing
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EXPECT YOUR EXPERT WILL REQUEST…
• Reports
• Witness statements
• Pictures
• Depositions
• Damages, personal and property
• Any other information you have gathered
• AND, your questions!
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YOUR EXPERT SHOULD THEN GIVE…
• A summary with POV (Point Of View-perspective)
• A Gap Analysis
• An investigative work plan, schedule and budget to fill the known gaps
• Ideas where unknown factors might be important, or become important
• Applicable standards, data and testing data to be evaluated
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COMMON TASKS IN WORK PLAN
• Site inspection • Vehicle inspection • Search and Review of applicable standards
– NHTSA/SAE/IIHS/ANSI/ASTM/IEC/EC/UL/CE/CSA – What are standards? (consensus) – How does that help?
• Analysis, Modeling, Reconciliation, Conclusion • Reporting, Preparing exhibits • Deposition • Trial
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SITE INSPECTION
• 6 DIMENSIONAL X,Y,Z,α,β,ζ
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BEFORE THE SITE INSPECTION
• Provided pictures are first but often misleading – Important
– But, scope limited
– Often, to close for geographic context (big picture)
• (My) First inspection is flat & digital from Google Maps – quick & inexpensive
• Second inspection using Accident Reconstruction Software - Also quick and inexpensive – ARAS HD, but there are others (Mapscene, PC-CRASH, etc.)
– Compare Google maps and ARAS HD
– 8 drivers who blindly followed gps
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MISLEADING PHOTOS
• Photography
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THE SITE INSPECTION
Its about detail • Dimensions • Angles • Friction • Structures • Vegetation • Curbs and sidewalks • Control signs • Anything that can impact the incident!
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MEASUREMENT CAN BE SIMPLE
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MEASUREMENT CAN BE COMPLEX
• Ground measurements are 3D (x, y and z) – Point to point using survey equipment (standard approach)
– Point cloud using automated scanners (latest technique)
– Often surveys are done before the expert gets involved and the expert needs to be able to use them
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OFFICIAL (REAL TIME) SITE INSPECTION
• PTP
• Point Cloud
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THE AR SITE INSPECTION
• Often months to years after the incident • Starting questions are developed from Google and 3D CAD modeling • On scene measurements
– Physical dimensions – COF measurement-drag sled – Acceleration measurement – Geography, east, west and height
• Photographs –then and now comparison important – changes to the landscape
• Surfaces • Repairs • new structure • improvements made in response
– Situational differences • dirt, grass, gravel • Environment, light and shadow, water, other
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THE AR SITE INSPECTION
• Use 3D CAD (ARAS HD) and explore/simulate
• Create 3-D features if needed
• Possibly create a 3D landscape
• Create a video
• Show views from different positions (POV)
– Validate or refute witness statements
– Demonstrate driver POV
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THE VEHICLE INSPECTION
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THE VEHICLE INSPECTION
• Pictures worth a 1000 words • Measurements using Photogrammetry both
before and after inspection-invaluable • Progress of destruction (in this NEXT case, not
just impact damage but trapping/ripping of the vehicle. Important in multi vehicle collisions
• Possible energy loss calculations due to metal bending
• Automated inspection using a point cloud can allow for automated crush analysis of energy
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Multi Vehicle Incident
• Who hit who when?
• Timeframes can be milli-seconds 31
Photogrammetry • Determining dimensions based on existing photos
• More photos improves accuracy
• It’s trigonometry
Calculated Actual Front corner of the book 4.25”, 35” 4.5”, 36” Rear corner of book 8”, 24.75” 8”, 27”
0,0
FRONT REAR
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STANDARDS & DATA
• Search for and Review of applicable standards – NHTSA/SAE/IIHS/ANSI/ASTM/IEC/EC/UL/CE/
– Standards and Data
– What are standards? • Generally Voluntary but can become law –public good – you must
have air bags!
• Contributory
• Represent opposing points of view of interested parties
• Consensus – must have air bags but not told how to build them
– If voluntary, how does that help? • Best thinking of the best thinkers
• If not this, then what?
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STANDARDS & DATA
• Standardized crash test reports – http://www.iihs.org/iihs/ratings/vehicle/v/chevrolet/equin
ox-4-door-suv/2012
• Narrow frontal (pole) crash • Side impact crash • Crush data • Vital statistics of manufactured autos
– Weight, front and rear track, overhang, CG – Moment of inertia - three axis – 4N6xprt; manufacturer’s and more data – ARAS HD
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HOW FAST?
• From skid marks
• From amount of crush
• From spent energy
• From vault
• From video
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MODEL DEMO
• Go to ARAS models
– Model 88th and Riverside
– Model Brisbane, Australia
– Make a new model from audience input
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Useful Websites
• National Highway Traffic Safety Administration-NHTSA http://www.safercar.gov/ • Insurance Institute for Highway Safety-IIHS http://www.iihs.org/ • FARO HD (ARAS HD) http://www.aras360.com/products/software/aras360-hd.html • 4N6xpt (Forensics Experts) http://ews-4n6xprt.com/ • REC-TEC http://www.rec-tec.com/ • Society of Automotive Engineers-SAE https://www.sae.org/ • American National Standards Institute-ANSI https://www.ansi.org/ • American Society for Testing Materials-ASTM https://www.astm.org/ • National Safety Concil NSC
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SURVEY
• Improve your understanding of AR?
• What is the most important thing you can do for me as your AR?
• Your Questions today?
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These principles apply to most any PI type case, or mechanical
engineering situation
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THE END