The phrase "the fundamental law of road congestion" refers to the finding that

congestion worsens in every city as its population grows.

drivers consistently underestimate how long their journeys will take.

the cost of maintaining roads rises faster than construction budgets allow.

the total distance driven rises in almost exact proportion to the lane miles added.

The passage identifies each of the following as a source of the additional traffic on a widened road EXCEPT

a rise in the number of vehicles owned per household nationally.

drivers switching to the widened road from alternative routes.

drivers making journeys they would not have made when the road was slower.

housing and commercial development that follows the new capacity.

The author's position on the widening of roads is that it

should be abandoned as a policy in all circumstances.

relieves congestion effectively provided enough capacity is added.

may be justified on other grounds, but not on the ground that it relieves congestion.

has been shown to leave corridors more congested than they were before.

According to the passage, pricing road use differs from adding capacity in that pricing

eliminates congestion altogether rather than merely reducing it.

is less expensive for governments to put in place.

benefits freight traffic more than it benefits private motorists.

rations scarce road space by willingness to pay rather than by delay.

Which of the following, if true, would most weaken the argument of the second paragraph?

Some widened corridors now carry substantially more freight than they did before widening.

In the metropolitan areas studied, population and employment grew at rates that would by themselves account for the observed rise in distance driven.

Travel times on widened roads fall sharply during the first year after construction is completed.

Lane miles are difficult to measure consistently from one metropolitan area to another.

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The Widening That Does Not Work: Induced Demand and Road Capacity

PRACTICE

100:00+4 −1MCQ Single Answer

Reading Passage

Congestion looks like a shortage of space. A road carries more vehicles than it was built for, traffic slows, and the obvious remedy is to build more road. For most of the twentieth century transport agencies acted on exactly this reasoning, and the widening of congested highways absorbed a large share of public infrastructure spending in many countries. However, studies comparing metropolitan areas over long periods have found that the remedy does not work as intended. Across the areas examined, the total distance driven rose almost in exact proportion to the lane miles added — a relationship now widely known as the fundamental law of road congestion. Three separate effects combine to produce it. Some drivers make trips they would not have made when the road was slower. Others shift onto the widened road from alternative routes, or move their journeys back into the peak hours they had learned to avoid. And over a longer horizon, housing and commercial development follows the new capacity, generating traffic that did not previously exist anywhere. Within a few years of a widening being completed, travel times on the corridor typically return to close to what they were before. None of this establishes that road building is always pointless. A road that creates a genuinely new connection is a different proposition from the widening of a corridor that is already saturated, and the gains to freight movement from more reliable highways are real and measurable. What the evidence does establish is that congestion relief is the wrong justification to offer. Where road space is the binding constraint, only pricing can do what capacity cannot: charging for use at busy times rations the space by willingness to pay, rather than allowing it to be rationed, as it is now, by delay.

Which of the following best expresses the main idea of the passage?