Because the interstate highway has been closed due to storm damage

Question

Because the interstate highway has been closed due to storm damage, congestion on other roads leading to the capital has increased by thirty percent. To resolve this issue, priority on these roads must be given to smaller vehicles.

Which of the following, if true, casts the most doubt on the effectiveness of the solution proposed above?

A. After a small southern city allocated different priorities to vehicles of different sizes, congestion on those roads was reported to decrease by 50 percent.
B. Since the interstate highway was closed, the number of cars on the road has increased by thirty percent.
C. Over eighty percent of the traffic on the other roads leading to the capital consists of smaller vehicles.
D. The major cause of congestion on the roads leading to the capital is the lack of adherence to traffic laws. 
E. Since the interstate highway was closed, the average amount of commuting time on roads leading into the capital has doubled.

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dhruv23320 · Answer

Correct answer: D

The argument assumes that congestion is caused by the type or size of vehicles using the roads, and therefore giving priority to smaller vehicles will reduce congestion.
Choice D seriously weakens this assumption. If the main reason for traffic congestion is actually poor adherence to traffic laws (such as blocking intersections, illegal parking, or ignoring signals), then changing vehicle priority based on size will not address the real cause of the problem. Even if smaller vehicles are prioritized, congestion would continue because the underlying issue is driver behavior, not vehicle size.
The other options do not weaken the proposal:

A supports the idea that prioritizing vehicle size can reduce congestion.
B and E describe the problem getting worse, not why the solution would fail.
C suggests that most vehicles are already small, but it does not explain why prioritizing them would be ineffective.

Therefore, D casts the most doubt on the effectiveness of the proposed solution.

postAlone · Answer

Option C
 
If most traffic = small vehicles already
 ↓
Giving them priority changes almost nothing
 ↓
Congestion remains essentially the same
 ↓
Solution is ineffective ✅

option d also weakens but:
 
  D requires an  extra inferential step   
  C  directly and immediately  shows the solution cannot work with  no extra assumptions

vasu1104 · Answer

interstate highway has been closed due to storm damage. 
 congestion on other roads have been increased by 30% 
 conclusion- solve this issue by giving priority to smaller vehicles on smaller roads.

A. After a small southern city allocated different priorities to vehicles of different sizes, congestion on those roads was reported to decrease by 50 percent. 
 this is irrelevant to argument. and if we have to take consideration of other cities plan, this somewhat strengthen it. reject.

B. Since the interstate highway was closed, the number of cars on the road has increased by thirty percent. 
 this talks about increase in number of cars but our conclusion is about giving priority to smaller cars to reduce congestion time. no impact. reject.

C. Over eighty percent of the traffic on the other roads leading to the capital consists of smaller vehicles. 
if majority of traffic is caused by smaller vehicles and now giving them the priority will make situation more worse to the problem. so this attacks the plans effectiveness. keep it

D. The major cause of congestion on the roads leading to the capital is the lack of adherence to traffic laws. 
this talks about what could be real cause for congestion but has no impact on the given plan to solve the issue. reject.

E. Since the interstate highway was closed, the average amount of commuting time on roads leading into the capital has doubled. 
 passage somewhat talks about the same issue. so nothing new. reject.

Because the interstate highway has been closed due to storm damage

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Because the interstate highway has been closed due to storm damage

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