A city councilor argues that banning privately owned cars from

Question

A city councilor argues that banning privately owned cars from the downtown area will substantially reduce the city’s overall air pollution levels. The councilor reasons that since privately owned cars account for a majority of vehicle traffic downtown, eliminating them from that area will significantly lower pollution citywide.

Which of the following, if true, most seriously weakens the councilor’s argument?

Which of the following, if true, most seriously weakens the councilor’s argument?

(A) Commercial delivery vehicles, which would still be permitted downtown, emit substantially more pollutants per vehicle than privately owned cars.
(B) Cities that have banned privately owned cars downtown have experienced economic growth in surrounding neighborhoods.
(C) Many commuters who currently drive privately owned cars downtown would instead switch to public transportation.
(D) Air pollution levels in the city have declined slightly in recent years despite an increase in downtown traffic.
(E) Residents living outside the downtown area contribute more to total vehicle miles traveled than downtown commuters.

guddo · Answer

A city councilor argues that banning privately owned cars from the downtown area will substantially reduce the city’s overall air pollution levels. The councilor reasons that since privately owned cars account for a majority of vehicle traffic downtown, eliminating them from that area will significantly lower pollution citywide.

Which of the following, if true, most seriously weakens the councilor’s argument?

Which of the following, if true, most seriously weakens the councilor’s argument?

The argument treats “most downtown vehicles” as if it means “most of the pollution that matters for the whole city.” I’d say the best weakener shows that private cars are not the main source of emissions downtown, so removing them would not cut pollution by much.

A. Commercial delivery vehicles, which would still be permitted downtown, emit substantially more pollutants per vehicle than privately owned cars.

This most seriously weakens. Even if private cars are most of the traffic, they might contribute less of the emissions if delivery vehicles pollute far more per vehicle. Then removing private cars removes a lot of vehicles but not necessarily a lot of pollution. That breaks the key link from “majority of traffic” to “big citywide pollution drop.” This is exactly  traffic share is not emissions share .

B. Cities that have banned privately owned cars downtown have experienced economic growth in surrounding neighborhoods.

This is about economic outcomes, not air pollution. It does not challenge the pollution reasoning.

C. Many commuters who currently drive privately owned cars downtown would instead switch to public transportation.

This supports the argument because it suggests fewer private cars will be driven, which would tend to reduce emissions.

D. Air pollution levels in the city have declined slightly in recent years despite an increase in downtown traffic.

This shows other factors also affect pollution, but it does not show that banning private cars downtown would fail to reduce pollution.

E. Residents living outside the downtown area contribute more to total vehicle miles traveled than downtown commuters.

This suggests a lot of driving happens outside downtown, but it does not directly show that the downtown private car ban would not reduce emissions substantially. It is weaker than (A), which directly targets the councilor’s central assumption.

Answer: (A)

egmat · Answer

The Argument: 
The councilor claims: Banning private cars downtown →  substantially  reduce  citywide  air pollution.

Why? Because private cars are the  majority  of downtown traffic.

The Hidden Assumption: 
The councilor assumes that  more vehicles = more pollution .

But  this is the trap!  Being the majority of  vehicles  doesn't mean being the majority of  pollution .

Why (A) Destroys the Argument: 
Commercial delivery vehicles:
- Will  still be permitted  downtown
- Emit  substantially more pollutants per vehicle

Think of it this way: 
-  100  private cars ×  1  unit pollution each =  100  units
-  20  delivery trucks ×  10  units pollution each =  200  units

Even after removing all  100  cars, the  200  units from trucks remain!

So banning private cars may  not  substantially reduce pollution at all.

Why Other Choices Fail: 
(B) Economic growth →  Irrelevant  to pollution
(C) Switching to public transit → Actually  strengthens  the argument!
(D) Past pollution trends → Doesn't address this specific policy
(E) Miles traveled outside downtown → Doesn't weaken downtown ban's effect

Here, the assumption is that vehicle COUNT determines pollution levels. Answer (A) shows that pollution PER VEHICLE matters more.

Answer: A

Usernamevisible · Answer

(D) is weaker because it does NOT isolate private cars as the cause of pollution.

(D) says:
> Air pollution declined slightly despite increased downtown traffic.

But this does NOT prove:
> “Private cars do not significantly contribute to pollution.”

Why?
Because many other factors could have reduced pollution at the same time:
* cleaner factories
* better fuel standards
* cleaner engines
* reduced industrial emissions

D gives a trend, but correlation does not mean causation.

GMAT rule:
> “Despite X increasing, Y decreased”
> is weak causal evidence unless other factors are controlled.

(A) is stronger because it attacks the exact assumption directly.

Councilor assumes:
> most traffic = most pollution
(A) says:
> wrong — remaining commercial vehicles emit far more pollution per vehicle.

So even if private cars are the majority of traffic, they may NOT be the majority source of pollution.

iamjayysingh · Answer

but wht if there is only 1 commercial delivery vehicle?

guddo · Answer

If there were  only 1 commercial delivery vehicle , then A would weaken much less.

But the option does not say there is only one. It refers to “commercial delivery vehicles” as a continuing category downtown.

So we should not add the extreme assumption “only one.” Under the option as written, A weakens because even if private cars are most vehicles, the remaining delivery vehicles could still produce a large share of pollution  per vehicle .

TheYagami · Answer

Option A only weakens the assumption that (most traffic equals most pollution), but it does not necessarily undermine the conclusion that banning private cars would significantly reduce pollution.
 
Even if delivery vehicles pollute more per vehicle, privately owned cars could still contribute a substantial share of total pollution, so removing them may still significantly lower citywide pollution.

sashankmvv1234 · Answer

someone please help.

the councilor argues that removing private vehicles will reduce air pollution. now commercial vehicles also cause reduce air pollution and we don't know their number. 
before banning: pollution from commercial vehicles: 1000 units
before banning: pollution from private vehicles: 100 units.
total pollution: 1100 units
if i remove the private vehicles then pollution is 1000 units. we don't know if the commercial vehicles have increased or decreased. so how can we say banning private vehicles won't reduce air pollution?

guddo · Answer

The argument does not need A to prove that pollution will not decrease at all.

It only needs A to weaken the claim that pollution will decrease  substantially citywide .

Your numbers actually show the point:

1100 to 1000 is a decrease, but it is small. Most pollution remains.

So A weakens because private cars may be the majority of vehicles but only a small share of emissions. That means removing them may reduce pollution only  slightly , not substantially.

guddo · Answer

You are treating the conclusion as “pollution will reduce at all.”

But the councilor claims it will  substantially reduce citywide pollution .

In your own numbers, pollution goes from 1100 to 1000. That is a reduction, but not a substantial one. Most pollution remains.

So A weakens because private cars may be most of the traffic but only a small share of the pollution. That breaks the move from  majority of vehicles  to “major pollution reduction.”

vasu1104 · Answer

privately owned cars account for majority of vehicle traffic downtown.
conclusion- ban the privately owned cars from downtown are will substantially lower the city's overall air pollution levels.

A now we have decided to ban the PO cars but then we realized that delivery vehicles release more pollution per vehicle than PO vehicles despite the fact that delivery vehicles numbers might be lower than PO. in that case the ban wont much of desired result. and this delivery vehicles either balance the pollution level to its original limit or will create more. so this helps enough to attack the validity of plan. keep.
B this has no impact on the given arguments here, reject. 
C thats good step and to be honest they are left with no other choice. so keep it up guyz. you are on way to reduce the pollution level. but everything aside this doesnt attack the conclusion in any way so reject.
D then why the hell are you troubling the privately owned car owners? leave them alone and let them enjoy their ride. reject.
E this talks about the comparison between miles driven by outside people and local people. it might make you root for this choice but driving more miles doesnt guarantee more pollution all time. what if they are having EV's? or what if they are driving in downtown areas? so this doesnt attack the plan on solid ground as does the choice A. so reject.

Albatross26 · Answer

But there is nothing to suggest the number of commercial delivery vehicles. How is the information in the option alone sufficient to conclude that it would weaken the councilor’s argument? There is no definite comparison between number of delivery vehicles. Could be that one commercial delivery vehicle emits pollutants equivalent to 10 privately owned cars but a 1000 cars are removed from downtown whereas just 5 commercial delivery vehicles travel in a day.

AbhishekP220108 · Answer

Hi  Albatross26  let me try to help

A city councilor argues that banning privately owned cars from the downtown area will substantially reduce the city’s overall air pollution levels. The councilor reasons that since privately owned cars account for a majority of vehicle traffic downtown, eliminating them from that area will significantly lower pollution citywide.

Which of the following, if true, most seriously weakens the councilor’s argument?

If we will look at the argument, its a cause-effect/plan-goal type

Cause/plan-eliminate private vehicle
Effect/goal-citywide overall air pollution will be significantly reduced

Basis of the conclusion-privately owned cars account for a majority of vehicle traffic downtown, eliminating them from that area will significantly lower pollution citywide.

Which of the following, if true, most seriously weakens the councilor’s argument?

To weaken we need to another reason for pollution

(A) Commercial delivery vehicles, which would still be permitted downtown, emit substantially more pollutants per vehicle than privately owned cars.- as you have said private owned cars are 1000 and commercial vehicles are 5 only. So removing PV will reduce overall pollution. Lets Consider this only right, so suppose each PV emit only 1 pollutants, 1000 pv 1000 pollutants, whereas 5 CV which emit substantially more pollutants per cv , lets say 1 CV emits 1000 pollutants then 5CV 5000 pollutants. Conclusion was substantially reduce overall air pollution even if we remove 1000 pollutants 5000 still persists, so its not substantially reduced.

Secondly you have said there was no mention of CV in an argument, well thats the point. That's what author missed. In weaken we need new info aligned with argument

Comparing this option with others accurately attacks the conclusion.

A city councilor argues that banning privately owned cars from

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A city councilor argues that banning privately owned cars from

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