Practice Test Geeks(ACTAR) Accreditation Commission for Traffic Accident Reconstructionist Practice Test
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Roadway Analysis 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 Roadway Analysis flashcards as text

  1. A vehicle leaves four tire marks totaling 120 feet on a surface with a drag factor of 0.70. Using the basic skid speed formula, what is the minimum speed estimate?

    Answer: Approximately 51 mph

    S = √(30 × d × f) = √(30 × 120 × 0.70) = √2520 ≈ 50.2 mph, rounded to approximately 51 mph.

  2. Which AASHTO design element directly determines the minimum sight distance available on a crest vertical curve?

    Answer: K-value

    The K-value (length per percent of A) determines how gently the crest rises and falls, directly controlling available sight distance.

  3. What does a negative super elevation (adverse crown) mean for a vehicle traversing a horizontal curve?

    Answer: The pavement slopes away from the curve center, adding to the centrifugal effect

    Adverse crown means the pavement tilts outward (away from the curve center), requiring more friction to prevent lateral sliding than a properly superelevated curve.

  4. In a traffic accident reconstruction, what is a 'critical speed' scuff mark?

    Answer: A curved tire mark deposited when a vehicle exceeds the critical speed of a curve

    Critical speed scuff marks are curved yaw marks that allow reconstructionists to calculate the speed at which the vehicle was traveling through a curve.

  5. How is the radius of a circular arc roadway curve typically measured in the field for accident reconstruction?

    Answer: By the chord-middle-ordinate method using a tape and string line

    The chord-middle-ordinate (chord-sagitta) method uses a known chord length and the middle ordinate to calculate R = C²/8M + M/2.

  6. Which pavement distress type most significantly reduces available friction for braking vehicles?

    Answer: Polished aggregate (bleeding/flushing)

    Polished aggregate or bleeding (excess asphalt) surfaces dramatically reduce macro-texture and available friction, lowering the effective drag factor.

  7. What is the significance of the 'point of curvature' (PC) in roadway geometry?

    Answer: The point where a tangent transitions into a horizontal circular curve

    The PC is the beginning of a horizontal circular curve where the straight tangent section ends and curved alignment begins.