Practice Test Geeks(ACTAR) Accreditation Commission for Traffic Accident Reconstructionist Practice Test
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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

  1. A reconstructionist uses the 'CRASH3' program or similar stiffness-based model. What does the stiffness coefficient 'B' represent?

    Answer: The rate of force increase per unit of additional crush depth

    The stiffness coefficient B represents the slope of the force-crush relationship — how much additional force is required per additional unit of crush.

  2. In a rollover reconstruction, which energy source is analyzed to estimate minimum vault speed?

    Answer: Kinetic energy at the initiation point

    The kinetic energy at roll initiation is analyzed, often using vault distance and height to back-calculate minimum pre-rollover speed.

  3. What does 'PDOF' stand for in the context of collision reconstruction?

    Answer: Principal Direction of Force

    PDOF — Principal Direction of Force — describes the resultant direction of the impact force applied to the vehicle.

  4. When analyzing a head-on collision between two vehicles of very different masses, which vehicle typically experiences the greater velocity change (delta-V)?

    Answer: The lighter vehicle

    By Newton's third law, the impulse is equal and opposite, so the lighter vehicle undergoes a greater velocity change (delta-V) because delta-V = impulse / mass.

  5. In the context of roadway evidence, what information do 'gouge marks' primarily provide to reconstructionists?

    Answer: Point of maximum engagement or the area of contact between vehicles

    Gouge marks are created when hard vehicle components contact the road surface and typically indicate the area of maximum engagement or point of impact.

  6. For a vehicle traveling on a banked curve, how does superelevation affect the effective drag factor used in critical-speed calculations?

    Answer: It increases effective drag on the high side and decreases it on the low side

    The roadway bank (superelevation) adds or subtracts from the lateral friction available, depending on which side of the curve the vehicle is sliding.

  7. A vehicle's EDR (Event Data Recorder) shows a recorded speed of 55 mph at 1 second before impact. What must a reconstructionist verify before using this data?

    Answer: The data's accuracy, calibration, and whether the sensor was functioning properly

    EDR data must be validated through proper download protocols and cross-checked against physical evidence to confirm accuracy and sensor integrity.