ACTAR Evidence Collection 5 — Questions and Answers
Question 1: Which characteristic of a crush damage profile is MOST useful for determining the vehicle's closing speed in a frontal barrier equivalent (FBE) analysis?
- The width of the damaged area
- The depth and distribution of crush across the vehicle's front (Correct answer)
- The color change in the damaged paint
- The height of the damage above the ground
Correct answer: The depth and distribution of crush across the vehicle's front
Crush depth and its distribution across the vehicle width are the primary inputs to stiffness-based (Campbell) energy methods used to calculate delta-V and closing speed.
Question 2: A reconstructionist finds a gap in the skid mark evidence where tires momentarily stopped skidding before resuming. This gap most likely indicates:
- A change in road surface material
- ABS activation cycling during the braking event (Correct answer)
- A second vehicle crossing over the first vehicle's path
- Driver intermittent brake application
Correct answer: ABS activation cycling during the braking event
ABS systems rapidly modulate brake pressure, causing the tire to alternately lock and release, producing characteristic gap patterns in the mark sequence.
Question 3: When surveying a crash scene that spans multiple lanes of a highway, what is the preferred sequence of evidence documentation before any scene is cleared?
- Measure distances first, then photograph, then sketch
- Overall scene photographs, then close-up photos, then measurements and sketches (Correct answer)
- Sketch first, then measure, then photograph from overhead only
- Collect physical evidence first, then photograph afterward
Correct answer: Overall scene photographs, then close-up photos, then measurements and sketches
Overall photographs establish scene context, close-ups capture specific evidence detail, and measurements/sketches follow to minimize scene disruption and preserve spatial relationships.
Question 4: The Daubert standard, as it applies to crash reconstruction evidence, requires that the expert's methodology be:
- Approved by a national police organization
- Based on peer-reviewed, testable science with known error rates (Correct answer)
- Derived exclusively from NHTSA publications
- Validated by at least three independent reconstructionists
Correct answer: Based on peer-reviewed, testable science with known error rates
Under Daubert, courts evaluate whether scientific testimony is based on sufficient facts, uses reliable methods that have been tested and peer-reviewed, and whether the method has been applied reliably to the case facts.
Question 5: Which EDR data parameter is MOST directly useful for determining whether a vehicle's brakes were applied in the 5 seconds before a crash?
- Engine RPM time history
- Brake switch status recorded in the pre-crash data frame (Correct answer)
- Transmission gear position
- Fuel system pressure data
Correct answer: Brake switch status recorded in the pre-crash data frame
EDR pre-crash data records brake switch status on a time-stepped basis, directly indicating whether the driver actuated the brake pedal and when.
Question 6: When reconstructing a crash involving a vehicle that caught fire, which evidence preservation priority should the reconstructionist emphasize?
- Documenting the fire suppression agent used by firefighters
- Photographing and mapping all identifiable physical evidence before fire investigation removes debris (Correct answer)
- Waiting for fire investigation to be fully completed before entering the scene
- Focusing solely on vehicle position and ignoring component debris
Correct answer: Photographing and mapping all identifiable physical evidence before fire investigation removes debris
Fire scenes are volatile and rapidly altered by suppression efforts and investigation; prompt photography and spatial documentation of all physical evidence preserves the pre-disturbance state.
Question 7: A reconstructionist notes that a vehicle has pre-impact tire marks from both front and rear axles that progressively widen apart laterally. This pattern is characteristic of:
- A vehicle braking in a straight line
- A vehicle entering a yaw (rotating about its vertical axis) before impact (Correct answer)
- A vehicle traveling over a crowned road surface
- A vehicle's tires being misaligned
Correct answer: A vehicle entering a yaw (rotating about its vertical axis) before impact
Progressively diverging tire marks from front and rear axles indicate the vehicle's rear was swinging outward relative to the front — the defining signature of a yaw maneuver.
ACTAR Evidence Collection 5
Which characteristic of a crush damage profile is MOST useful for determining the vehicle's closing speed in a frontal barrier equivalent (FBE) analysis?