According to the manual, doubling your vehicle's speed has what effect on its stopping distance?
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A.
It triples.
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B.
It quadruples. Correct
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C.
It stays the same.
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D.
It doubles.
The answer is "It quadruples."
Doubling your speed quadruples your vehicle's stopping distance. D is the trap because linear thinking says double-in equals double-out, but stopping distance grows with the square of speed, not in step with it.
The traps in the wrong answers
A. It triples.
The manual gives a specific multiple, and three is not it. This answer picks a middle number between doubles and quadruples that the manual never uses.
C. It stays the same.
Stopping distance grows sharply with speed and does not stay constant. This answer confuses stopping distance with reaction time, which the manual treats as a separate factor.
D. It doubles.
Speed doubles, but stopping distance grows with the square of speed, not linearly. This answer applies everyday linear thinking to a rule the manual states as a squared effect.
This question tests your knowledge of Speed Limits in Illinois. Source: Illinois Rules of the Road, "Vehicle Speed," p.84..
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