The Urban Planner's Claim here is that the plan of reducing overall traffic volume is based on the
assumption that by
reducing the number of single-occupancy vehicles on the roads, overall traffic volume will decrease. To answer the question here, it is important to define what an assumption is. An assumption is the crucial unstated logical link between the premise and conclusion and it must be true in order for the argument to be valid. Since the aim is to decrease traffic volume through the reduction of single-occupancy vehicles we need to look at the statement which directly threatens the reduction of single-occupancy vehicles.
With this information let us go through the answer choices.
(A) Many drivers prefer to travel alone due to the flexibility and privacy it offers, even when financial incentives are offered for carpooling.
Even though many drivers prefer to travel alone, that does not mean that the number of single-occupancy vehicles on the roads cannot decrease. How do you define many? Many drivers can prefer to travel alone and at the same time, many drivers can also be tempted by financial incentives and switch to carpooling.
(B) The tax incentives provided for carpooling are structured to disproportionately benefit higher-income drivers, potentially leading to less participation among lower-income commuters.
The words "potentially" and "less participation" are not strong indicators that change is not possible. And even if all single-occupancy high-income drivers switch to carpooling, this would still be considered a win. We do not know the ratio of higher-income drivers to lower-income commuters.
(C) Public transportation systems are likely to see an increase in use due to higher awareness of environmental issues, regardless of the carpooling initiative.
That is perfectly fine. Public transportation can see and increase as can the carpooling initiative. These two instances are not mutually exclusive.
(D) Most traffic congestion is due to commercial vehicles, which are not affected by carpooling incentives as they cannot realistically share vehicle space.
Here we have an interesting answer choice because the word "most" is used, meaning the vast majority. It states that most vehicles are commercial and they will not be tempted by carpooling incentives because they cannot share vehicle space. Here we have a logistical obstacle as to why carpooling is not possible for commercial vehicles; and since most traffic congestion is due to these vehicles, then we cannot reduce the number of single-occupancy cars.
(E) The tax incentives for carpooling will initially cost the city a significant amount in lost tax revenue, which could have been used for other traffic reduction measures.
We are not concerned with other traffic reduction measures, we care about reducing the number of single-occupancy vehicles. Moreover, we are not talking about opportunity cost and are not concerned with the costs pertaining to the city.
Therefore the answer is D
Bunuel
Urban Planner's Claim: The city plans to reduce traffic congestion by implementing a carpooling initiative that encourages drivers to share rides by offering tax incentives. The plan is based on the assumption that by reducing the number of single-occupancy vehicles on the roads, overall traffic volume will decrease.
Which of the following, if true, raises the most serious doubt regarding the effectiveness of the city's plan to decrease traffic congestion?
(A) Many drivers prefer to travel alone due to the flexibility and privacy it offers, even when financial incentives are offered for carpooling.
(B) The tax incentives provided for carpooling are structured to disproportionately benefit higher-income drivers, potentially leading to less participation among lower-income commuters.
(C) Public transportation systems are likely to see an increase in use due to higher awareness of environmental issues, regardless of the carpooling initiative.
(D) Most traffic congestion is due to commercial vehicles, which are not affected by carpooling incentives as they cannot realistically share vehicle space.
(E) The tax incentives for carpooling will initially cost the city a significant amount in lost tax revenue, which could have been used for other traffic reduction measures.