When officials in Tannersburg released their plan to widen the citys

When officials in Tannersburg released their plan to widen the city’s main roads,

Officials at a city T made public their plan to widen the city’s main roads.
When they did this, what happened?

environmentalists protested that widened roads would attract more traffic and lead to increased air pollution.

Environmentalists protested. Their concern was that wide roads would attract more traffic and lead to more 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.

In response to the environmentalists’ concern, T’s officials said that pollution control devices are most effective at higher speeds and that widened roads would allow higher speeds.

Thus, T’s officials indicated that widened roads could bring down air pollution.

However, this effect can hardly be expected to offset the effect pointed out by environmentalists, since __________.

“However” indicates a contrast. The author says that the effect of widened roads mentioned by T’s officials is not likely to offset the increased pollution because of widened roads.

There are two opposing factors at play here:

1. Wider roads → faster traffic → more effective pollution-control devices → less pollution – an advantage of wider roads
2. Wider roads → more traffic → more pollution – a disadvantage of wider roads

The author believes that the advantage of wider roads will likely not compensate for the disadvantage. I.e., on balance, wider roads will likely lead to more pollution.

We’re looking for an option that supports the author’s point.

Thus, we’re looking for an option that suggests that overall pollution will increase if the roads are widened.

Predicting Possible Answers

1. An option indicating that a lot of people are waiting for the roads to get widened to buy new cars, i.e., once the roads are widened, many people will buy cars and increase the traffic on the roads.
2. An option indicating that the existing roads allow for much greater vehicle speed than people currently drive at. (So, people perhaps don’t want to drive faster than they currently do.) Thus, wider roads would not result in greater vehicle speed. (Thus, we have no reason to expect better functioning air pollution control devices)

A. increases in traffic volume generally produce decreases in the average speed of traffic unless roads are widened

Incorrect. The meaning of this statement is that

if roads are not widened, increases in traffic volume generally produce decreases in the average speed of traffic.

The statement presents a problem (a decrease in the average traffic speed, which might lead to a decrease in the effectiveness of air pollution control devices) with not widening the roads. By doing so, the statement supports the widening of the roads.

Thus, the statement is in the opposite direction of what we want. We want an option to indicate a problem with the widening of roads (specifically that the widening of roads will lead to an overall increase in air pollution).

We can, thus, rule out this option.

One may ask: does this option weaken the point mentioned in the last statement?

The answer is No.

The option indicates that with the widening of roads, increased traffic will not lead to a decrease in the average traffic speed. (However, the option doesn’t indicate that the widening of roads will lead to an increase in average traffic speed.)

If there is no decrease in the average traffic speed, there is no decrease in the effectiveness of air pollution control devices. In such a case, there will not be more pollution because of the reduced effectiveness of air pollution control devices.

However, the increased traffic due to wider roads (as given in the passage) is still expected to lead to more pollution. Thus, the point mentioned in the last statement is not weakened.

B. several of the roads that are slated for widening will have to be closed temporarily while construction is underway

Incorrect. This option has no impact either on the statement by city officials or on the environmentalists’ concern.

The temporary closure of the roads doesn’t impact whether widened roads will lead to more pollution or less pollution.

C. most of the air pollution generated by urban traffic comes from vehicles that do not have functioning pollution-control devices

Correct. This option says that most air pollution generated by urban vehicles comes from vehicles that do not have functioning pollution-control devices. If so, increased average speed due to widened roads will not help reduce pollution. If many vehicles do not even have these pollution-control devices in the first place, at what speeds they act at optimum levels becomes a moot point. Thus, we have a reason to believe that the increased air pollution due to more traffic will not be offset by a reduction in pollution due to better functioning pollution control devices.

D. the newly widened roads will not have increased traffic volume if the roads that must be used to reach them are inadequate

Incorrect. Let’s first evaluate the following version of D:

D1: the newly widened roads will not have increased traffic volume

If D1 is the case, the environmentalists’ concern is weakened. Perhaps, there will not be much increase in pollution. Thus, we have a reason to believe that the reduction in pollution due to faster speeds will offset the increase in pollution due to more traffic (since there is not much increase in traffic).

Thus, this option is in the opposite direction of what we want.

Now, let’s get back to the original option D:

If the roads that must be used to reach them are inadequate, the newly widened roads will not have increased traffic volume

This option presents a specific situation in which the newly widened roads will not have increased traffic volume.

Which situation?

The situation in which the roads that are needed to reach the newly widened roads are inadequate.

So, if people don’t have a good way to reach the newly widened roads, these roads will not have increased traffic volume.

However, we don’t know whether this will be the case in city T. Besides, even if it is, the option suggests something opposite to what we want, as I explained above.

E. a vehicle traveling on a route that goes through Tannersburg will spend less time on Tannersburg’s roads once the roads are widened

Incorrect. If such vehicles spend less time on the roads, we have a reason to believe that their average speed has increased and that there will be less pollution in T.

Thus, this option suggests a benefit of widened roads and is thus opposite to what we want.