During a commercial driver safety presentation, an instructor reviews the human-factor pha… — Commercial Driver's License (CDL) General Knowledge Exam

During a commercial driver safety presentation, an instructor reviews the human-factor phases involved in stopping a commercial vehicle at a highway cruising speed of $55\text{ mph}$ . Which statement correctly distinguishes perception distance from reaction distance?

A
Perception distance is the distance traveled while moving the foot from the accelerator to the brake pedal (taking about $0.75\text{ seconds}$ ), while reaction distance is the distance traveled from the instant a hazard is spotted until the brain recognizes it (taking about $1.75\text{ seconds}$ ).
B
Perception distance is the distance traveled until compressed air reaches the brake chambers, while reaction distance is the distance required for mechanical friction to bring the wheels to a complete stop.
Perception distance is the distance traveled from the instant eyes see a hazard until the brain recognizes it (about $1.75\text{ seconds}$ or $142\text{ feet}$ at $55\text{ mph}$ ), while reaction distance is the distance traveled while moving the foot to apply the brake pedal (about $0.75\text{ seconds}$ or $61\text{ feet}$ at $55\text{ mph}$ ).Cevap
D
Perception distance is determined by allocating 1 second per 10 feet of vehicle length, while reaction distance requires adding an extra 1 second whenever travel speed exceeds $40\text{ mph}$ .

Cevap

Perception distance is the distance traveled from seeing a hazard until the brain recognizes it (about

1.75\text{ seconds}

142\text{ feet}

55\text{ mph}

), whereas reaction distance is the distance traveled while moving the foot to press the brake pedal (about

0.75\text{ seconds}

61\text{ feet}

55\text{ mph}

Perception distance is defined as the distance a commercial motor vehicle travels from the time the driver sees a hazard until the brain recognizes it (averaging

1.75\text{ seconds}

, which equals roughly

142\text{ feet}

55\text{ mph}

). Reaction distance is the distance traveled while the driver physically moves their foot from the accelerator to push the brake pedal (averaging

0.75\text{ seconds}

, which equals roughly

61\text{ feet}

55\text{ mph}

Adım Adım Çözüm

Define perception distance and identify its benchmark values for an alert commercial driver.

Perception distance covers the interval from hazard visualization to cognitive recognition, lasting an average of

1.75\text{ seconds}

and spanning approximately

142\text{ feet}

55\text{ mph}

Perception is the initial cognitive phase of the stopping sequence before any physical driver action begins.

Define reaction distance and identify its benchmark values.

Reaction distance covers the physical movement from accelerator release to pressing the brake pedal, averaging

0.75\text{ seconds}

and spanning approximately

61\text{ feet}

55\text{ mph}

Reaction represents the human motor response phase immediately following cognitive recognition.

Differentiate driver human-factor phases from mechanical vehicle braking components and following distance formulas.

Driver-controlled pre-braking consists solely of perception distance plus reaction distance, totaling

2.5\text{ seconds}

(

203\text{ feet}

55\text{ mph}

) before vehicle braking mechanisms engage.

Distinguishing human cognitive/motor phases from mechanical brake lag and space-ahead following guidelines ensures correct identification.

Anahtar Kavram

Stopping Distance Components: Perception Distance vs. Reaction Distance

Tahmini Süre:1m 0s

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