ACTAR Evidence Collection 2 — Questions and Answers
Question 1: When collecting tire mark evidence at a crash scene, what is the primary reason for measuring the WIDTH of a yaw mark?
- To calculate vehicle speed
- To identify the tire make and model
- To determine which axle produced the mark (Correct answer)
- To estimate road surface friction
Correct answer: To determine which axle produced the mark
The width of a yaw mark corresponds to the tire tread width, which helps identify whether it was produced by a front or rear axle.
Question 2: Which photographic technique is most effective for capturing the texture and depth of gouge marks in asphalt?
- Overhead flash photography
- Oblique lighting (raking light) photography (Correct answer)
- Infrared photography
- Wide-angle lens panoramic photography
Correct answer: Oblique lighting (raking light) photography
Oblique or raking light cast at a low angle accentuates surface irregularities, making gouge depth and texture visible in photographs.
Question 3: A reconstructionist discovers fluid stains at a crash scene. What is the FIRST step before collecting a fluid sample for laboratory analysis?
- Apply a preservative chemical to the stain
- Photograph and document the location and dimensions of the stain (Correct answer)
- Scrape the stain directly into a collection container
- Measure the distance from the stain to the nearest vehicle
Correct answer: Photograph and document the location and dimensions of the stain
Documentation of the stain's position, size, and relationship to other evidence must occur before any collection that disturbs the scene.
Question 4: Under the Federal Rules of Evidence, physical evidence from a crash scene must be accompanied by a proper chain of custody to ensure:
- The evidence is admissible and has not been altered or tampered with (Correct answer)
- The evidence is stored at room temperature
- Law enforcement personnel collected the evidence
- The evidence was collected within 24 hours of the crash
Correct answer: The evidence is admissible and has not been altered or tampered with
Chain of custody documentation establishes that evidence integrity was maintained from collection through courtroom presentation.
Question 5: When documenting airbag deployment evidence, which component provides the most reliable indication of occupant contact during a crash?
- The airbag housing color
- Fabric transfer and biological material on the airbag surface (Correct answer)
- The airbag deployment threshold voltage
- The position of the steering wheel after impact
Correct answer: Fabric transfer and biological material on the airbag surface
Fabric transfer, blood, or skin cells on the airbag surface directly indicates occupant contact and body position at deployment.
Question 6: Which type of evidence is MOST susceptible to degradation or loss if the crash scene is not documented promptly?
- Structural deformation of vehicles
- Skid mark evidence on roadway surfaces (Correct answer)
- Vehicle VIN plates
- Roadway gradient measurements
Correct answer: Skid mark evidence on roadway surfaces
Tire marks on road surfaces are quickly erased by traffic, weather, and road maintenance, making prompt documentation critical.
Question 7: An ACTAR reconstructionist is collecting event data recorder (EDR) information. What is a critical legal consideration before downloading EDR data from a vehicle?
- The vehicle must be at least 10 years old
- Ownership and authorization or a court order must be established (Correct answer)
- The EDR must be physically removed from the vehicle first
- Law enforcement must be present during the download
Correct answer: Ownership and authorization or a court order must be established
EDR data is legally owned by the vehicle owner, and accessing it without authorization or a court order may render it inadmissible and expose the reconstructionist to legal liability.
ACTAR Evidence Collection 2
When collecting tire mark evidence at a crash scene, what is the primary reason for measuring the WIDTH of a yaw mark?