A government study indicates that raising speed limits

Question

A government study indicates that raising speed limits to reflect the actual average speeds of traffic on level, straight stretches of high-speed roadways reduces the accident rate. Since the actual average speed for level, straight stretches of high-speed roadways tends to be 120 kilometers per hour (75 miles per hour), that should be set as a uniform national speed limit for level, straight stretches of all such roadways.

Which one of the following principles, if valid, most helps to justify the reasoning above?

(A) Uniform national speed limits should apply only to high-speed roadways.

(B) Traffic laws applying to high-speed roadways should apply uniformly across the nation.

(C) A uniform national speed limit for high-speed roadways should be set only if all such roadways have roughly equal average speeds of traffic.

(D) Long-standing laws that are widely violated are probably not good laws.

(E) Any measure that reduces the rate of traffic accidents should be implemented.

temitope992 · Answer

Can somebody explain to me why option C is wrong and option E is correct

batraavneet81 · Answer

Option C is giving a condition which is inherent to the argument. More like an assumption.

Option E is an inference which is also strengthening the argument

(FYI, I also marked C)

TheWrongGrammer · Answer

In E it talks about “any” measure but the passage talks about one specific measure. So why is it correct to extend 1 measure to “any” measure?

Posted from my mobile device

nikkyxthomas · Answer

Don't get why C is incorrect. Option E seems like a generalisation. Can someone explain?

GautamKhanduja · Answer

Option E seems like an inference and not the justification for reasoning. Although I did not like C but it looked best out of the given choices.
Can someone explain please  KarishmaB   MartyTargetTestPrep   GMATNinja

chetan2u · Answer

A government study indicates that raising speed limits to reflect the actual average speeds of traffic on level, straight stretches of high-speed roadways reduces the accident rate. Since the actual average speed for level, straight stretches of high-speed roadways tends to be 120 kilometers per hour (75 miles per hour), that should be set as a uniform national speed limit for level, straight stretches of all such roadways.

The argument consists of two statements:-
Premise: Outcome of a study 
Conclusion: Implementation of the result of the outcome. 
LOGIC: Study showed that accidents went down by raising speed limits to average speed seen on level & straight patches of highways. Uniform speed limit to be increased to 75mph as it is the actual average on such stretches.

Which one of the following principles, if valid, most helps to justify the reasoning above?
 So, we are looking for a ‘strengthener’. There could be various other effects of raising the speed limit. 
It could include: Making a separate lane/road for slower speed vehicles, more pollution, fate of commercial complexes if any on the stretch, requirement of more service lanes etc  
The point is that there may be some negative effects too of raising speed limit. So, we require an option that would justify increasing speed limit based on just one advantage, which is lesser rate of accidents.

(A) Uniform national speed limits should apply only to high-speed roadways.
 How does it matter to the argument on what is being done on other roads.  
Out of scope.

(B) Traffic laws applying to high-speed roadways should apply uniformly across the nation.
 Again, out of scope. Uniform application does not strengthen the argument. The correct option should strengthen ‘the application’ part.

(C) A uniform national speed limit for high-speed roadways should be set only if all such roadways have roughly equal average speeds of traffic.
 Lot of queries on top on this option. This is not justifying the application as it is merely putting a condition to ‘the application’. 
If the raising speed limit to 75mph meets the criteria, the proposal goes through. If not, then the proposal is shelved off. 
Not a strengthener.

(D) Long-standing laws that are widely violated are probably not good laws.
 Out of scope.

(E) Any measure that reduces the rate of traffic accidents should be implemented.
 So, if a measure reduces the rate of accident, it should be implemented.  
Here, the study has shown that rate of accident would go down if the speed limit is raised to average. 
Thus, the option justifies the implementation.

KarishmaB · Answer

The question stem is looking for a strengthener.

Premises:
Raising speed limits to actual average speeds on a kind of roadways reduces the accident rate.
The actual average speed for these roadways tends to be 75 mph. (this is what it usually is for all such roadways)

Conclusion: 75 mph should be set as speed limit for all such roadways.

Note that we are given that usually on such roadways, the actual avg speed is 75 mph. The author's opinion is that since setting it at 75 mph will reduce accident rate, the administration should set speed limit as 75 mph. 
What will strengthen the conclusion hat this is what the administration should implement? If we are given that a measure that reduces the rate of accidents should be implemented, it helps justify the conclusion. Try to put it in along with the premises to see if it helps.

Premises:
Raising speed limits to actual average speeds on a kind of roadways reduces the accident rate.
 Any measure that reduces the rate of accidents should be implemented 
The actual average speed for these roadways tends to be 75 mph. (this is what it usually is for all such roadways)

Conclusion: 75 mph should be set as speed limit for all such roadways.

The conclusion does make more sense now.

Answer (E)

Note that it is not necessary that every measure that reduces rate of accidents should be implemented. We do end up assuming it but it is not necessary. What if setting a higher speed limit leads to fewer but more severe accidents. Then one may want to debate on whether it should be implemented. But if it is given as a premise that "any measure that reduces the rate of accidents should be implemented" then the conclusion that "75 mph should be implemented" makes sense.

Now put option (C) in the premises.

Premises:
Raising speed limits to actual average speeds on a kind of roadways reduces the accident rate.
The actual average speed for these roadways tends to be 75 mph. (this is what it usually is for all such roadways)
 A uniform national speed limit for high-speed roadways should be set only if all such roadways have roughly equal average speeds of traffic.

Conclusion: 75 mph should be set as speed limit for all such roadways.

Does the conclusion make more sense? Will the author use option (C) as a fact to support his conclusion?

unraveled · Answer

A government study indicates that raising speed limits to reflect the actual average speeds of traffic on level, straight stretches of high-speed roadways reduces the accident rate. Since the actual average speed for level, straight stretches of high-speed roadways tends to be 120 kilometers per hour (75 miles per hour), that should be set as a uniform national speed limit for level, straight stretches of all such roadways.

Which one of the following principles, if valid, most helps to justify the reasoning above?

(A) Uniform national speed limits should apply only to high-speed roadways.

(B) Traffic laws applying to high-speed roadways should apply uniformly across the nation.

(C) A uniform national speed limit for high-speed roadways should be set only if all such roadways have roughly equal average speeds of traffic.

(D) Long-standing laws that are widely violated are probably not good laws.

(E) Any measure that reduces the rate of traffic accidents should be implemented.
Like anyone of those 40%, I chose C sadly.

For me it was between C and E but didn't gave much attention to E as it looked frivolous. However, is that condition laid out in C necessary? Not necessarily. Even if it is the case how would effectivity of the claim - setting of uniform national speed limit for level - in the passage is ensured. Hence many further levels of assumptions are required to be made.

Answer E.

rvgmat12 · Answer

OA from PS Forum-

Strengthen—PR. The correct answer choice is (E)

This stimulus consists of two premises and a conclusion. The first premise is that the government study shows that raising the speed limit to actual average speeds on level, straight, high-speed roadways reduces the accident rate. Next, we are told that the average speed for such roads is 75 miles per hour (120 kph) and the author thus concludes that all such roads should have that speed limit. Note that the scope in all three sentences is identical and consistent (i.e, “level, straight stretches of high-speed roadways”). Since the scope is appropriate, the author could justifiably conclude that raising the speed limit to 75 mph on these roadways would reduce the accident rate. Instead, the author concludes that the speed limit should be raised. While this may seem an insignificant leap in logic, the author’s shift from a predicted outcome to a recommended approach is unsupported without first establishing the desirability of the outcome. The correct answer will be a principle that supports this leap.

Answer choice (A): The author’s argument is not strengthened by demonstrating that such changes should not be made on any other kind of road. The consistent scope of both premises and the conclusion eliminates the need to deal with other kinds of roads and renders this principle irrelevant.

Answer choice (B): By the same token as (A), the consistent scope throughout our stimulus frees us from the need to consider other roads. Furthermore, suggesting that the speed limit on all roads should be raised to 75 mph mistakenly generalizes the findings of the government study, which was specific to level, straight stretches of high-speed roadways.

Answer choice (C): Our premises indicate that the speed limit for these types of roads “tends to be” 75 mph. If “tends to be” is interpreted as “all such roadways have roughly equal average speeds”, then we have satisfied a necessary condition of this principle, which would allow but not justify our reasoning. If this principle is understood to imply a higher standard than our premise has met, then (C) would weaken the reasoning above. In neither case does this principle help to justify the author’s conclusion.

Answer choice (D): (D) raises a number of questions. Are current speed limit laws long-standing? Does an average speed of 75 mph indicate that laws are “widely violated” or could a few extremely fast cars account for the average speed? If speed limit laws are long-standing and widely violated, does classifying them as “probably bad laws” justify the conclusion? What does this principle have to do with the rationale of reducing accidents? There are far too many issues with (D) to use it as justification of the reasoning in the stimulus.

Answer choice (E): This is the correct answer choice. The government study gives us a measure that reduces the rate of traffic accidents. The author concludes that this measure should be implemented. The best way to justify this reasoning is apply a principle that “any measure that reduces the rate of traffic accidents should be implemented.” Such a principle effectively bridges the gap between the expected outcome of the measure and the desirability of implementing it.

Mavisdu1017 · Answer

KarishmaB  hello expert, I didn’t well understand what you mean. I just post my thinking here, and hope you to address my question. Thanks in advance. 
As the premise: Because the actual average speed for such highway roads tends to be the same (75mph), and “tends to be 75” means “all such roadways have roughly equal average speeds”, so we can set a (uniform) national speed limit - the conclusion.
C: A (uniform) national speed limit for high-speed roadways should be set ONLY IF the speed of such roads tends to be the same - strengthen the reasoning. 
Where am I wrong?

KarishmaB · Answer

Your conclusion says "Do A."
Option (C) says "Do A only if condition B is satisfied."

Is option (C) helping your case? Is it strengthening what you are saying? Is it giving a reason why one SHOULD do A? If anything, it is raising doubts and conditions on when A should be done. Think of it as a dialogue.

You: Do A.
I: Do A only if condition B is satisfied.

Am I your supporter here? If it is still not clear, think what word I will use (Yes/No) before saying it.

You: Do A.
I:  "No, do A only if condition B is satisfied"  or will I say: "Yes, do A only if condition B is satisfied."

Isn't the highlighted more meaningful?

Akarsh97 · Answer

In my understanding option C is dealing with the conclusion of the argument i.e. setting the speed limit to the average speed of the highway.

But the option E is dealing with the reasoning behind the conclusion i.e. setting the speed limit to the average speed reduces the no. of accident.

A government study indicates that raising speed limits

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A government study indicates that raising speed limits

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