Scene Documentation 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 Scene Documentation flashcards as text
When a crash scene has been partially altered before the reconstructionist arrives, what is the most important first step?
Answer: Document the current condition thoroughly and note specifically what alterations occurred and by whom
Documenting the current condition while noting all known alterations preserves what evidence remains and establishes the limits of the reconstruction's evidentiary basis.
In crash scene photogrammetry, what are 'control points' and why are they necessary?
Answer: Surveyed ground points with known coordinates used to scale, orient, and georeference the photogrammetric model
Control points with known X, Y, Z coordinates allow photogrammetric software to accurately scale and orient the 3D model to real-world dimensions.
What measurement technique is used to locate scene features when a total station or GPS is unavailable and only a measuring tape is at hand?
Answer: Triangulation using measurements from two or more known fixed reference points
Triangulation from two known fixed points (such as utility poles or signs) allows accurate location of features using only linear tape measurements.
Which statement correctly describes the role of a 'scene diagram' versus a 'scene map' in crash reconstruction documentation?
Answer: A scene diagram is a freehand sketch made in the field; a scene map is an accurately scaled drawing prepared from field measurements
A field sketch (diagram) captures rough layout and notes quickly, while a scaled map drawn from precise measurements is the formal product used for analysis.
What effect does a camera lens with a wide focal length (e.g., 16 mm) have on crash scene photographs compared to a normal focal length (e.g., 50 mm)?
Answer: It exaggerates perspective, making distances between objects appear greater than in reality
Wide-angle lenses expand apparent depth, causing distances between scene features to look larger than normal human vision perceives, which can be misleading in courtroom presentations.
When documenting crash scene evidence in inclement weather, which preservation method is appropriate for protecting perishable tire marks?
Answer: Photograph and measure immediately, then cover with plastic sheeting or cones before rain reaches the marks
Immediate photography and measurement followed by physical covering preserves the evidence record before rainfall can wash away or obscure tire mark deposits.
Which of the following best defines 'oblique photography' as used in crash scene documentation?
Answer: Photography taken at an angle to the scene rather than vertically, providing perspective views of evidence
Oblique photography captures angled perspective views that show the three-dimensional relationships between scene elements, complementing overhead and close-up images.