In 1974 the speed limit on highways in the United States was reduced

Question

In 1974 the speed limit on highways in the United States was reduced to 55 miles per hour in order to save fuel. In the first 12 months after the change, the rate of highway fatalities dropped 15 percent, the sharpest one-year drop in history. Over the next 10 years, the fatality rate declined by another 25 percent. It follows that the 1974 reduction in the speed limit saved many lives.

Which one of the following, if true, most strengthens the argument?

(A) The 1974 fuel shortage cut driving sharply for more than a year.

(B) There was no decline in the rate of highway fatalities during the twelfth year following the reduction in the speed limit.

(C) Since 1974 automobile manufacturers have been required by law to install lifesaving equipment, such as seat belts, in all new cars.

(D) The fatality rate in highway accidents involving motorists driving faster than 55 miles per hour is much higher than in
highway accidents that do not involve motorists driving at such speeds.

(E) Motorists are more likely to avoid accidents by matching their speed to that of the surrounding highway traffic than by driving at faster or slower speeds.

Bunuel · Accepted Answer

OFFICIAL EXPLANATION

(A) No. If fuel shortages caused Americans to drive less, it would be expected that the annual rate of traffic fatalities would decrease. While the argument claims that the reduced speed limit saved lives, this answer-choice indicates an alternative possibility and therefore weakens the argument.

(B) No. This does not explain why traffic fatalities decreased during the first eleven years following the speed limit reduction.

(C) No. This would weaken the argument because the safety equipment, not the reduced speed limit, might be responsible for the decreased rate of fatalities.

(D) Yes.  This strongly indicates that the decrease in speed reduced the chance of fatal injuries during automobile accidents. A lower speed limit (presuming some people obey it) should therefore reduce the rate of highway fatalities.

(E) No. This suggests that accidents can be avoided by matching speeds with surrounding traffic—regardless of what the speed is. In this case, a lower speed limit should not affect the number of accidents. Note, although this implies the probability of an accident shouldn’t be affected by the speed, conceivably the chance of fatalities if an accident does occur might be affected by the speed. However, there’s another answer-choice which directly addresses this issue.

sandeep211986 · Answer

I will go with D.
If the highway accidents involving motorists driving faster than 55 miles per hour is much higher than in
highway accidents that do not involve motorists driving at such speeds then with the speed limit law accidents will reduce.
Initially I was torn between D and E but finally selected D as in option E the word likely makes it a bit shady as likely means not surely.
Experts please clarify if my understanding is correct.

Rgards,
Sandeep
Kudos plz.

Zarevl · Answer

I choose D

(A) The 1974 fuel shortage cut driving sharply for more than a year.  - out of scope

(B) There was no decline in the rate of highway fatalities during the twelfth year following the reduction in the speed limit.
 - weakens the argument

(C) Since 1974 automobile manufacturers have been required by law to install lifesaving equipment, such as seat belts, in all new cars.  - weakens

(D) The fatality rate in highway accidents involving motorists driving faster than 55 miles per hour is much higher than in
highway accidents that do not involve motorists driving at such speeds.  - my choice

(E) Motorists are more likely to avoid accidents by matching their speed to that of the surrounding highway traffic than by driving at faster or slower speeds.  - weakens the argument. The flow can move at a speed higher or lower than the allowed, and the probability of an accident depences on the driving style

stne · Answer

It was between D and E finally chose D.

abd15 · Answer

Between D and E.. Only D talks about fatality rate.. So D wins clearly

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chesstitans · Answer

there is a little confusion here
D has at least 2 pattern. The first is to compare one to each other group. The second is it is the only option that has direct link with the matter in the argument.

Skywalker18 · Answer

Conclusion: the drop in the speed limit saved many lives

WHY: the speed limit was reduced to 55, and after one year the rate of highway fatalities dropped by 15 %, and over the next ten years it dropped another 25 percent.

Looking at this core, I noticed two problems:

1. the author seems to be playing with percentages. Just because the percentages went down, it doesn't mean more lives were saved. It could be that the drop in the speed limit led to many more people driving, so even though we had a drop in the rate of fatalities, more people were dying each year.

2. Author mistakes correlation for causation.

Just because the drop in speed limit coincided with the drop in the rate of fatalities, it doesn't mean the two are related. It could be that something else, such as a national campaign to promote better driving, was the cause.

To strengthen the first issue, we have to show that the number of people driving did not increase to such an extent whereby we could not conclude that many lives were saved.

To strengthen the second issue, we have to rule out the possibility that some other factor caused the drop. It's important to note that when we are given correlation/causation flaws on Strengthen and Weaken questions, the answer choice usually tests our understanding of this. So it is likely that we will be tested on the second issue.

A. this was very tempting for me at first because it seems to get at our first issue. That there was no increase in driving. However, if that's that case, it would provide an alternative cause for the drop in fatalities, so it can't be correct.

B. is irrelevant because we don't know anything about the 12th year. Maybe the speed limit was increased again.

C. gives us an alternative cause, which means it would weaken the argument.

D. gives us a classic way to strengthen a correlation flaw on the LSAT - by showing that when you don't have the cause, you won't get the effect.

55mph --> lower rate

D: don't have 55mph --> rate is not as high

This strengthens our correlation and is the correct answer.

E. not impact on argument.

septwibowo · Answer

Cause and Effect passage, my favorite!

Lowering speed limit (CAUSE) means saving many lives (EFFECT)
  
(A) The 1974 fuel shortage cut driving sharply for more than a year.  ???

(B) There was no decline in the rate of highway fatalities during the twelfth year following the reduction in the speed limit.  Why this option contradicts the premise?

(C) Since 1974 automobile manufacturers have been required by law to install lifesaving equipment, such as seat belts, in all new cars.  WEAKEN by providing alternate cause. Eliminate on a solid ground.

(D) The fatality rate in highway accidents involving motorists driving faster than 55 miles per hour is much higher than in
highway accidents that do not involve motorists driving at such speeds.  BINGO! strengthen the premise or CAUSE that states that >55 means more fatal accidents.
 
(E) Motorists are more likely to avoid accidents by matching their speed to that of the surrounding highway traffic than by driving at faster or slower speeds.  Doesn't talk about fatality.

TheNightKing · Answer

Skywalker18 
Hello!
I just want to say this: the detail with which you provide explanations across the forum is just extraordinary. Be it CR,RC or SC. Way too good.

Thank you!

unraveled · Answer

In 1974 the speed limit on highways in the United States was reduced to 55 miles per hour in order to save fuel. In the first 12 months after the change, the rate of highway fatalities dropped 15 percent, the sharpest one-year drop in history. Over the next 10 years, the fatality rate declined by another 25 percent. It follows that the 1974 reduction in the speed limit saved many lives.

Which one of the following, if true, most strengthens the argument?

(A) The 1974  fuel shortage cut driving sharply  for more than a year. - WRONG. Weakener. Alternative reason behind such a drop.

(B) There was  no decline in the rate of highway fatalities during the twelfth year  following the reduction in the speed limit. - WRONG. Irrelevant.

(C) Since 1974 automobile manufacturers have been required by law to  install lifesaving equipment, such as seat belts , in all new cars. - Weakener. Alternative reason behind such a drop.

(D) The fatality rate in highway accidents involving motorists driving faster than 55 miles per hour is much higher than in highway accidents that do not involve motorists driving at such speeds. - CORRECT. As easy as it can get.

(E) Motorists are more likely to  avoid accidents by matching their speed to that of the surrounding highway traffic  than by driving at faster or slower speeds. - WRONG. Weakener. Alternative reason behind such a drop.

Answer D.

Adnani · Answer

E is trap answer....
I believe understanding the trap answers are equally important

Posted from my mobile device

VerbalBot · Answer

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In 1974 the speed limit on highways in the United States was reduced

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