ACTAR Human Factors 4

Question 1

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?

Accepted Answer

Approximately 240 feet

Answer

PRT distance ≈ 80.7 ft/s × 1.5 s = 121 ft; braking distance = v²/(2 × 0.7 × 32.2) ≈ 120 ft; total ≈ 241 ft.

Question 2

Older drivers (65+) generally exhibit longer perception-reaction times primarily due to which physiological change?

Accepted Answer

Slower central nervous system processing speed

Answer

Age-related slowing of central neural processing is the primary cause of longer reaction times in older drivers, independent of sensory changes.

Question 3

A driver claims they 'looked but didn't see' a motorcyclist before a collision. Which human factors explanation best accounts for this?

Accepted Answer

The motorcycle was in a visual scan but not attended to (looked but not seen)

Answer

'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.

Question 4

Which of the following describes the 'motion camouflage' effect relevant to motorcycle crashes?

Accepted Answer

A closing vehicle appears stationary when approaching head-on because its bearing angle does not change

Answer

When an object approaches on a constant bearing (direct interception path), it appears stationary against the background—making an oncoming motorcycle difficult to detect.

Question 5

What does research on cell phone distraction indicate about hands-free vs. hand-held phone conversations while driving?

Accepted Answer

Both produce comparable cognitive distraction and crash risk elevation

Answer

Research, including NHTSA studies, shows that hands-free and hand-held phone conversations produce similar cognitive distraction and comparable crash risk increases.

(ACTAR) Accreditation Commission for Traffic Accident Reconstructionist Practice Test

(ACTAR) Accreditation Commission for Traffic Accident Reconstructionist Practice Test

ACTAR Human Factors 4