Quote:
Increasing the speed limit to 65 miles per hour or more on highways is dangerous and only leads to more accidents. Whenever the highway speed has been increased, accident rates have increased in that state. Maine raised its turnpike speed to 65 mph in November, and more fatal accidents occurred in December than any other month in the year. Highway fatalities in December and January combined were up 18% from November.
All of the following are valid criticisms of this argument EXCEPT
A. it does not explain why the speed limit was originally set at 55 mph.
B. it does not specify whether the accident rate increase was in accidents only on the highways where the speed limit was increased or on all highways.
C. it does not consider other possible causes for increases in accidents, such as winter weather driving conditions in Maine.
D. it only cites statistics for one state.
E. it does not acknowledge that speed is not the only cause of accidents
A is the best answer. First, let us rephrase the question as a standard strengthen/weaken/assumption etc. question type. Essentially, this is an "EXCEPT" question, which could be re-framed as "All of the following WEAKEN the argument EXCEPT". With this in mind, let us approach the argument:
Here, the argument states that raising the highway speed limit to 65 mph or more is dangerous and leads to more accidents. It further goes on to cite accident-based statistics related to Maine, which support the idea that the speed limit should not be increased in Maine. The data confirm that whenever the speed limits have increased, so have the accident rates. The figures also show that increased accident rates (up by 18%) since when Maine raised its turnpike speed in November.
Now, let us think of the possible ways to weaken the argument. One fundamental assumption made by the author is that correlation = a causal connection. This absolutely does not have the case. For example, there could be other (unrelated to speed) causes for the increased accident rates, and the connection between increasing the highway speed limit and greater accident rate could be purely coincidental (and not necessarily a cause-effect relationship). Therefore, any option(s) which state something along this line of reasoning would weaken the argument. Since this is a "WEAKEN Except" question, we want to
eliminate the options that weaken the argument. This eliminates C and E.
Furthermore, another way to weaken the argument would be to question the data provided. The author is drawing an overly broad, generalized conclusion based on "increasing the speed limit on highways", whereas the statistics he provides are only for Maine. Clearly, based on statistics for just country/state/town, we cannot draw a generalization. In other words, we cannot go from the premise of "Apples are red" to the conclusion "Fruits are red" [since there would be fruits other than apples]. This eliminates D.
Lastly, the accident data show that there was an overall 18% combined increase in the highway fatalities in the months of December and January in Maine. However, this does not differentiate between highways where the speed limit was increased vs those where it remained the same. It could be the case that most of the increase in the overall accident rate was occurring on highways where the speed limit remained the same, and was due to a reason entirely unrelated to speed (for example, wild animals jumping in front of cars, a gang of robbers being active in the area, etc.]. Once again, the author fails to distinguish between correlation and causality, and this line of reasoning could weaken the argument. This eliminates B.
Option A is the correct answer. Option A actually acts as a strengthener, because if increasing the speed limit to 65mph increased the accident rates, then the argument would serve as a perfectly adequate explanation of why the original speed limit was on the lower side of 55 mph. Since Option A strengthens the argument, this must be the correct answer to our "WEAKEN Except" question.