Single correct option
The passage below is followed by four summaries. Choose the one that best captures its essence.
Urban planners have long assumed that adding lanes to congested highways reduces traffic. Yet study after study documents the opposite: new capacity fills up within a few years, sometimes months, as commuters who previously avoided the route, changed their travel times, or used other modes shift back to driving. The phenomenon, known as induced demand, means that road capacity does not simply accommodate a fixed quantity of trips; it actively shapes how many trips people choose to make. Cities that have instead invested in transit, congestion pricing or bike infrastructure have, in several documented cases, seen sustained reductions in traffic that lane expansions rarely achieve.
Urban planners have long assumed that adding lanes to congested highways reduces traffic. Yet study after study documents the opposite: new capacity fills up within a few years, sometimes months, as commuters who previously avoided the route, changed their travel times, or used other modes shift back to driving. The phenomenon, known as induced demand, means that road capacity does not simply accommodate a fixed quantity of trips; it actively shapes how many trips people choose to make. Cities that have instead invested in transit, congestion pricing or bike infrastructure have, in several documented cases, seen sustained reductions in traffic that lane expansions rarely achieve.
- A. Building new highway lanes is always a waste of public money and should never be attempted under any circumstances.
- B. Because new road capacity tends to generate its own additional traffic, expanding highways rarely relieves congestion for long, whereas transit and pricing measures have shown more lasting results.
- C. Congestion pricing is the only effective solution to urban traffic problems, and all other measures have failed.
- D. Commuters change their travel behaviour unpredictably, making it impossible for planners to design effective transport policy.
Show answer and solution
Answer: (B) Because new road capacity tends to generate its own additional traffic, expanding highways rarely relieves congestion for long, whereas transit and pricing measures have shown more lasting results.
The passage's core claim is that added highway capacity induces new demand and so fails to durably cut congestion, while alternatives like transit and pricing have worked better. Option B captures both the induced-demand mechanism and the comparative point about alternatives. A overstates into an absolute ban; C wrongly claims pricing is the 'only' solution when the passage lists multiple alternatives; D distorts the point into unpredictability rather than a systematic effect.
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