Accident Reconstruction Tech and Heavy Trucks

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1 Accident Reconstruction Tech and Heavy Trucks September 22, 2016 Ashley (Al) Dunn, Ph.D., P.E. 1

2 We re All Here Because.. Stuff Happens 2

3 Accident Reconstruction Trucks are Different 3

4 The Truck is 20 TIMES Heavier than your SUV! = 4

5 Heavy Truck Accidents Injury severity is >20 times higher for passenger car occupants versus truck occupants. Why? Mass ratio - can exceed 20:1 Stiffness: Heavy trucks and trailers are primarily designed to haul weight not absorb collision energy Bumper heights: Front bumpers, tractor frame, trailer deck and rear ICC bar are higher than passenger car bumpers. Results in engagement of comparatively weaker structures. 5

6 Effect of Mass and Stiffness Disparity Collision forces between vehicles are equal and opposite. 6

7 Effect of Mass and Stiffness Disparity Collision forces between vehicles are equal and opposite. 7

8 The who The when The where The what The how What is Accident Reconstruction? 8

9 DATA COLLECTION Commercial Vehicle Inspection Report Objective Truck-Related Information: Brake Conditions Brake Adjustments* Axle Weights Crash Damage Other deficiencies, such as structural issues with frame Caveat: this information is not always correct! 9 9

10 DATA COLLECTION Commercial Vehicle Inspection Report 2 outta 10 ain t bad! Is it? 10

11 Accident Reconstruction Step 2: Document Evidence measure, photograph, collect, PRESERVE 11

12 DOCUMENT EVIDENCE ASAP Roadway evidence (tire marks, scratches / gouges) Skid/Braking Yaw 12

13 DOCUMENT EVIDENCE ASAP Vehicle Inspection (Special Circumstances): Brakes Conspicuity (Lighting, reflectors, clothing) Seat Belts, Guides Others (Suspension, Tire)? 13

14 The Infamous Slack Adjuster not a lazy person who works for an insurance company... applied released 14

15 Now, we ll put the Brake Together A I R 15

16 DOCUMENT EVIDENCE ASAP Vehicle Inspection (Special Circumstances): Seat Belts - Evidence of Use Close-up 16

17 DOCUMENT EVIDENCE ASAP Engine Control Module Data Extraction: It is Engine Specific, not truck specific Cummins, Caterpillar, Detroit Diesel Is the record option activated? What data is retrievable? What are the best means to extract the NECESSARY data? Onboard Direct to Module Exemplar engine/truck 17

18 VEHICLE DRAWING Measure and Document Crush 18

19 Tools Available to Your Expert Old School and High-Tech 19

20 Traditional Tools 20

21 High Tech Tools 21

22 Photo Modeling aka, Photogrammetry SCENE DRAWING 22

23 Photo Modeling ACCIDENT SCENE 23

24 ACCIDENT SCENE Truck POFR 24

25 Photo Modeling ACCIDENT SCENE 25

26 Scene Diagram 26

27 Event Data Recorder Heavy Truck ECM Download V = 8.0 mph triggers save 27

28 Event Data Recorder (EDR) Passenger Car Percent of Wide Open Throttle Vehicle Speed (MPH) Engine Speed (RPM) Brake Switch Status (On or Off) 28

29 High Tech Vehicle Site Survey Vehicle / Scene Scans with FARO Scanner 29

30 DOCUMENT EVIDENCE FARO Scanner Vehicle Scan this is NOT a photograph 30

31 DOCUMENT EVIDENCE FARO Scanner 31

32 DOCUMENT EVIDENCE FARO Scanner 32

33 DOCUMENT EVIDENCE FARO Scanner Data Scene HVE Sim 33

34 DOCUMENT EVIDENCE FARO Scanner Data Scene HVE Sim 34

35 ANALYSIS OPTIONS Testing Calculations Simulation 35

36 Vehicle Mechanics / Dynamics 1. Speed calculations Crush Energy & Force Conservation of Momentum Conservation of Energy Force Balance 36

37 Vehicle Mechanics / Dynamics 2. Time-Speed Distance Calculations Set Bounds on the Possible Evaluate Perception/Reaction Times Is a Scenario Physically Possible? 37

38 Vehicle Dynamics and Modeling 38

39 Accident Reconstruction Simulation HVE-SIMON 39

40 Full Scale Testing 40

41 Full Scale Testing Suspension Failure? 41

42 The Accident Rollover - Fire Suspension Failure? 42

43 Full Scale Testing Road Edge Recovery 43

44 Full Scale Testing Closing Speed Determination Panning Video 44

45 Full Scale Testing Closing Speed Determination Overhead High-Speed Video 45

46 Full Scale Testing Closing Speed Determination Goal: Duplicate Damage on Subject Vehicle Accident Vehicle Test - Target Vehicle 46

47 Full Scale Testing Truck ABS Wet Braking in a Curve ABS - Tractor ON / Trailer ON 47

48 Full Scale Testing Truck ABS Wet Braking in a Curve ABS - Tractor ON / Trailer OFF 48

49 Trial Exhibits Animation Oversized Load and Pedestrian 49

50 Thank You for your time today! Ashley L. (Al) Dunn, Ph.D., P.E. 50

Accident Reconstruction & Vehicle Data Recovery Systems and Uses

Research Engineers, Inc. (919) 781-7730 7730 Collision Analysis Engineering Animation Accident Reconstruction & Vehicle Data Recovery Systems and Uses Bill Kluge Thursday, May 21, 2009 Accident Reconstruction