When officials in Tannersburg released their plan to widen the city's main roads, environmentalists protested that widened roads would attract...
GMAT Critical Reasoning : (CR) Questions
When officials in Tannersburg released their plan to widen the city's main roads, environmentalists protested that widened roads would attract more traffic and lead to increased air pollution. In response, city officials pointed out that today's pollution-control devices are at their most effective in vehicles traveling at higher speeds and that widening roads would increase the average speed of traffic. However, this effect can hardly be expected to offset the effect pointed out by environmentalists, since ________.
Which of the following most logically completes the argument?
Passage Analysis:
| Text from Passage | Analysis |
| When officials in Tannersburg released their plan to widen the city's main roads, environmentalists protested that widened roads would attract more traffic and lead to increased air pollution. |
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| In response, city officials pointed out that today's pollution-control devices are at their most effective in vehicles traveling at higher speeds and that widening roads would increase the average speed of traffic. |
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| However, this effect can hardly be expected to offset the effect pointed out by environmentalists, since ______. |
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Argument Flow:
We start with environmentalists worried about more traffic and pollution from wider roads. City officials counter by saying faster traffic actually pollutes less per mile. The author then argues this speed benefit won't be enough to overcome the pollution problem from more traffic.
Main Conclusion:
The city officials' argument about reduced pollution from higher speeds won't be enough to offset the increased pollution from more traffic that environmentalists predict.
Logical Structure:
The author is setting up a 'but wait, there's more' situation - even if the city is right about speed reducing pollution, there's still some missing piece that makes the environmentalists' concern more valid. We need to find what makes the volume increase more significant than the speed improvement.
Prethinking:
Question type:
Logically Completes - We need to find a reason why the city officials' counterargument won't be strong enough to overcome the environmentalists' concern about increased pollution from more traffic.
Precision of Claims
The key claims involve quantity comparisons: the environmentalists say MORE traffic leads to MORE pollution, while city officials say HIGHER speeds lead to LESS pollution per vehicle. We need to explain why the pollution reduction from speed won't offset the pollution increase from volume.
Strategy
For logically completes questions, we need to find the missing piece that makes the author's reasoning sound. The author believes the city's speed argument won't work against the environmentalists' traffic volume argument. We need scenarios that explain why better efficiency per car can't overcome the problem of having way more cars total.
This choice talks about how traffic volume affects speed, but we need something that explains why the city's speed argument won't work against the environmentalists' pollution concerns. This choice actually seems to support road widening by suggesting it prevents speed decreases, which doesn't help explain why the city's argument fails.
The temporary road closures during construction are irrelevant to the long-term pollution debate between environmentalists and city officials. This doesn't address why faster speeds won't offset increased traffic pollution once construction is complete.
This is our answer! If most urban traffic pollution comes from vehicles WITHOUT functioning pollution-control devices, then the city officials' entire argument falls apart. They're claiming that pollution-control devices work better at higher speeds, but if most cars don't even have working devices, this benefit becomes meaningless. No matter how fast these cars go, they'll still pollute heavily because their devices don't work.
This talks about traffic volume on connecting roads, but doesn't address the core issue of why pollution-control device efficiency at higher speeds won't offset the pollution from increased traffic volume. It's about traffic patterns, not pollution comparison.
This mentions that cars will spend less time on Tannersburg roads, which might actually support the city's position by suggesting less total pollution exposure time. This doesn't explain why the speed argument fails against the volume argument.