Bunuel wrote:
Editorialist: Some people argue that highway speed limits should be increased to reflect the actual average speeds of highway drivers, which are currently 10 to 20 percent higher than posted speed limits. Any such increase would greatly decrease highway safety, however; as past experience teaches, higher average highway speeds would result, since even though most drivers who currently violate posted speed limits would obey higher ones, almost all drivers who obey current speed limits would likely increase their speed.
Which one of the following, if true, most seriously weakens the editorialist’s argument?
(A) Some drivers who obey current speed limits would not change their speeds after the introduction of the new speed limits.
(B) Uniformity of speeds among vehicles is more important for highway safety than is a low average highway speed.
(C) Most drivers who drive 10 to 20 percent faster than current speed limits have never been involved in a highway accident.
(D) Some drivers who violate current speed limits would also violate higher speed limits.
(E) Most drivers who violate current speed limits determine their speeds by what they believe to be safe in the situation.
EXPLANATION FROM Fox LSAT
My first idea on this question is, “Do higher speeds actually decrease highway safety?” Because if not, then the logic here just makes no sense. We’re asked to weaken the argument, so my prediction is, “Higher speeds do not decrease highway safety.” That seems almost too easy. Let’s look at the answer choices.
A) This doesn’t kill the argument, because even if some drivers don’t increase their speeds, others who
did increase their speeds could still hurt safety. I doubt this is it.
B) If this is true, then the argument is in trouble. The author says that if higher limits are posted, the drivers who currently break the old limits will
obey the new limits. And the author says that almost all drivers who obey the old limits will increase their speed after new limits are posted. This would seem to suggest that there will be more uniformity of speed between cars at the new higher limit. If uniformity outweighs average speed for safety concerns, then how would raising the limit cause a net decrease in safety? I like this answer.
C) Whether people have “usually” been involved in accidents is in no way relevant. The only thing relevant here is whether the new higher limits will decrease safety. This is a terrible answer.
D) This is bad in the way that answer A is bad. The editorialist seems to acknowledge that a few drivers won’t act as predicted. The editorialist says “most drivers,” and “almost all drivers.” This logic leaves open the inevitable outliers who don’t follow the pattern. I don’t see how this really weakens the argument.
E) I’m not sure this is relevant, because the editorialist says that under the new, higher limit most drivers are going to be obeying the law. So I don’t think E would even apply to the scenario of new higher limits.
Answer B was a pretty good answer, so we’ve got to go with that.
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