By how much does stopping distance increase when you double your speed?

Prepare effectively for your Alabama CDL Class A Permit Test with our comprehensive study resources, including flashcards and multiple choice questions. Learn with detailed explanations to ensure you're ready for the actual exam!

Multiple Choice

By how much does stopping distance increase when you double your speed?

Explanation:
Stopping distance grows much faster than your speed because it has two parts: reaction distance and braking distance. Reaction distance increases in direct proportion to speed, while braking distance increases with the square of speed. So when you double your speed, the reaction part becomes twice as long, and the braking part becomes four times as long. Since braking distance is typically the larger portion of the total stopping distance at normal driving speeds, the overall stopping distance ends up about four times longer. That’s why the correct answer is four times the original stopping distance.

Stopping distance grows much faster than your speed because it has two parts: reaction distance and braking distance. Reaction distance increases in direct proportion to speed, while braking distance increases with the square of speed. So when you double your speed, the reaction part becomes twice as long, and the braking part becomes four times as long. Since braking distance is typically the larger portion of the total stopping distance at normal driving speeds, the overall stopping distance ends up about four times longer. That’s why the correct answer is four times the original stopping distance.

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