A heavy combination vehicle is traveling at 45 mph on an unlit secondary highway. The vehicle's low-beam headlights provide visibility up to 200 feet ahead, while the vehicle's total stopping distance—combining perception distance, reaction distance, and actual braking distance—is approximately 290 feet. Which of the following statements correctly identifies the safety hazard and the necessary driver response?
- AThe vehicle is operating within safe margins because perception and reaction distances take place before mechanical braking begins, meaning only braking distance needs to fit inside the illuminated area.
- The driver is overdriving the headlights and must decrease road speed so that total stopping distance does not exceed the illuminated sight distance.Cevap
- CThe driver should maintain speed and reduce following distance behind a lead vehicle to use its taillights for additional forward visibility.
- DThe vehicle can safely sustain speed by flashing high beams intermittently, relying on momentary flashes to extend perception distance beyond the stopping threshold.
Cevap
The driver is overdriving the headlights and must decrease road speed so that total stopping distance does not exceed the illuminated sight distance.
At night, commercial motor vehicle operators must never overdrive their headlights. Total stopping distance is the sum of perception distance, reaction distance, and braking distance. When total stopping distance (290 feet) exceeds the illuminated range (200 feet), the driver cannot stop before striking an unexpected hazard first spotted at the beam limit. The only safe corrective action is to slow down until total stopping distance fits entirely within the illuminated area.
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Overdriving Headlights and Total Stopping Distance at Night
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