CDL · CDL general knowledge
Which statement about speed and stopping a bus is correct?
Correct answer: At 40 mph you need roughly four times the stopping distance that you need at 20 mph.
Answer options
- AKeeping to the posted speed limit always gives you room to stop safely
- BTotal stopping distance counts only the distance traveled after the brakes are applied
- CAt 40 mph you need roughly four times the stopping distance that you need at 20 mph Correct
- DEvery 10 mph above 20 mph adds one second to the time it takes to stop
Why
Braking distance grows much faster than speed, so twice the speed takes roughly four times the room to stop. Total stopping distance also includes the ground covered while you perceive a hazard and react, and a posted limit does not guarantee you can stop in time.
About this question
Topic: CDL general knowledge License: CDL
Part of these practice sets:
Where it applies: Asked in every state.
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This question is part of Controlling Speed (24 questions). Take the full set and check your score.
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