Visibility & Lighting Conditions 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 Visibility & Lighting Conditions flashcards as text
In traffic accident reconstruction, 'overdriving headlights' occurs when:
Answer: A driver travels at a speed where stopping distance exceeds headlight illumination distance
Overdriving headlights means the vehicle is traveling too fast to stop within the distance illuminated by the headlights, a key concept in nighttime collision analysis.
What is the standard low-beam headlight illumination distance commonly used in nighttime accident reconstruction analyses?
Answer: 150–160 feet
Standard low-beam headlights illuminate approximately 150–160 feet ahead, a figure derived from FMVSS 108 and widely used in reconstruction to calculate available nighttime sight distance.
Which unit is used to measure the retroreflectivity of pavement markings in traffic engineering and accident reconstruction?
Answer: Millicandela per square meter per lux (mcd/m²/lux)
Retroreflectivity of pavement markings is quantified in mcd/m²/lux, the unit used in FHWA minimum retroreflectivity guidelines for assessing marking visibility.
The term 'conspicuity' in accident reconstruction refers to:
Answer: The ease with which an object can be detected and recognized by a driver
Conspicuity describes how easily a driver can detect and identify an object in the roadway environment, which is critical in pedestrian and nighttime collision analyses.
In nighttime accident reconstruction, the 'available sight distance' is primarily limited by:
Answer: The illumination distance of the vehicle's headlights
At night, available sight distance is determined by the effective illumination range of the headlights, establishing how far ahead a driver can detect objects.
What atmospheric condition is most likely to cause 'disability glare' for drivers at night?
Answer: Oncoming vehicle headlights directed toward the driver
Oncoming headlights directed toward a driver create disability glare, temporarily reducing the driver's ability to detect objects in their path by scattering light within the eye.
When reconstructing a nighttime collision involving a pedestrian wearing dark clothing, which factor is MOST critical in determining the driver's available reaction distance?
Answer: The detection distance of the pedestrian under prevailing headlight illumination
Detection distance—the distance at which the driver could first perceive the dark-clad pedestrian under the headlight conditions—is the key factor in determining whether sufficient time and distance existed to stop.