Human Factors 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 Human Factors flashcards as text
What is the average total stopping distance (perception-reaction + braking) for a driver traveling at 55 mph on dry pavement with a PRT of 1.5 seconds and a deceleration rate of 0.7g?
Answer: Approximately 240 feet
PRT distance ≈ 80.7 ft/s × 1.5 s = 121 ft; braking distance = v²/(2 × 0.7 × 32.2) ≈ 120 ft; total ≈ 241 ft.
Older drivers (65+) generally exhibit longer perception-reaction times primarily due to which physiological change?
Answer: Slower central nervous system processing speed
Age-related slowing of central neural processing is the primary cause of longer reaction times in older drivers, independent of sensory changes.
A driver claims they 'looked but didn't see' a motorcyclist before a collision. Which human factors explanation best accounts for this?
Answer: The motorcycle was in a visual scan but not attended to (looked but not seen)
'Looked but failed to see' is a recognized phenomenon where a glance occurs but attention is not allocated to the target, resulting in no conscious perception.
Which of the following describes the 'motion camouflage' effect relevant to motorcycle crashes?
Answer: A closing vehicle appears stationary when approaching head-on because its bearing angle does not change
When an object approaches on a constant bearing (direct interception path), it appears stationary against the background—making an oncoming motorcycle difficult to detect.
What does research on cell phone distraction indicate about hands-free vs. hand-held phone conversations while driving?
Answer: Both produce comparable cognitive distraction and crash risk elevation
Research, including NHTSA studies, shows that hands-free and hand-held phone conversations produce similar cognitive distraction and comparable crash risk increases.
In a rear-end collision analysis, which factor most directly determines whether a following driver had adequate time to perceive and react to a lead vehicle braking?
Answer: Time-to-collision (TTC) at the moment brake lights activated
TTC at brake light activation determines whether the following driver had sufficient margin (typically ≥ PRT + braking time) to avoid collision.
Which criterion is used to determine whether a pre-impact event was within a driver's 'avoidance window'?
Answer: Whether sufficient time and distance existed for the driver to perceive, react, and complete an avoidance maneuver
The avoidance window requires that time-distance analysis confirm perception was possible and that reaction plus maneuver could have been completed before impact.