Evidence Collection Flashcards
7 cards from real ACTAR practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Evidence Collection flashcards as text
When documenting occupant kinematics using interior damage evidence, which feature of steering wheel deformation is MOST informative about driver contact forces?
Answer: The direction and magnitude of rim offset from its original plane
Steering wheel rim deformation direction and magnitude indicates the vector and approximate force of the driver's chest or hand contact during the crash.
A crash reconstructionist is examining a vehicle that impacted a guardrail. Which piece of evidence best establishes the vehicle's initial contact point on the guardrail?
Answer: The leading edge of paint transfer and gouging on the guardrail beam
The leading edge of paint transfer and initial gouge marks on the guardrail surface identify where the vehicle first contacted the structure.
Which type of witness evidence should be treated with the MOST caution when reconstructing vehicle speed?
Answer: A stationary pedestrian who briefly observed the vehicles
Stationary witnesses observing a brief event have limited ability to accurately estimate vehicle speed, as speed perception is highly unreliable for untrained observers.
When collecting glass fracture evidence at a crash scene, the pattern of radial and concentric fractures can help determine:
Answer: The direction and sequence of impact forces applied to the glass
Radial fractures propagate outward from the point of impact, and concentric fractures form around it; sequence analysis reveals whether multiple impacts occurred and in what order.
A reconstructionist collects a soil sample from a vehicle's undercarriage following a crash that occurred in a rural area. This evidence is MOST useful for:
Answer: Corroborating or refuting the alleged crash location
Soil composition analysis can be compared to samples from the alleged crash site to confirm or dispute where the vehicle traveled before or during the incident.
In a pedestrian fatality investigation, which evidence at the impact point is MOST important for establishing the pedestrian's position relative to the vehicle at first contact?
Answer: The leading edge of blood and biological trace material on the roadway
The leading edge of blood, tissue, or biological evidence on the roadway marks the first contact point between vehicle and pedestrian.
When an ACTAR reconstructionist photographs tire marks using photogrammetry for later measurement, what calibration step is essential for accurate results?
Answer: Placing calibrated scale references (targets) within the photographic frame
Calibrated scale targets with known dimensions provide the photogrammetry software with the scale reference needed to convert pixel measurements to real-world dimensions.