Collision Analysis & Reconstruction 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 Collision Analysis & Reconstruction flashcards as text
In a two-vehicle in-line collision where one vehicle rear-ends another, which post-collision indicator best helps establish the struck vehicle's departure speed?
Answer: The struck vehicle's post-impact tire marks and point of rest
The struck vehicle's post-impact tire marks and final rest position, combined with scene drag factor, allow calculation of its post-impact departure speed.
Which of the following best describes the 'coefficient of restitution' (e) in a collision?
Answer: The ratio of relative separation speed to relative approach speed along the line of impact
The coefficient of restitution equals the relative separation velocity divided by the relative approach velocity, indicating how elastic the collision was.
When using photogrammetry to reconstruct a collision scene, what is the primary advantage over traditional tape measurements?
Answer: It allows accurate measurements to be extracted from photographs after the scene has been cleared
Photogrammetry enables precise measurements to be extracted from calibrated photographs long after physical evidence has been removed from the scene.
In a T-bone intersection collision, the reconstructionist uses the 'time-distance' method. What does this analysis determine?
Answer: Each driver's position and speed at critical moments before impact
Time-distance analysis plots each vehicle's position against time to determine speeds, positions, and sightlines at critical pre-crash moments.
A vehicle slides to rest on a level surface leaving 80 feet of skid marks. If the drag factor is 0.70, what was the vehicle's speed at the beginning of the skid?
Answer: 41 mph
Using S = √(30 × d × f) = √(30 × 80 × 0.70) = √1680 ≈ 41 mph.
Which type of collision analysis accounts for the rotation of vehicles after impact in addition to their translational motion?
Answer: Combined linear and angular momentum analysis
Combined linear and angular momentum analysis accounts for both translational and rotational motion that vehicles exhibit after off-center impacts.
What is the significance of the 'engagement distance' in a collision reconstruction?
Answer: The distance over which the two vehicles were in contact during the collision
Engagement distance is the length of the contact zone between the two vehicles during collision, relevant to crush analysis and impact duration estimation.