Passage:

Some urban economists once treated congestion pricing as a purely technical fix: charge drivers a fee that reflects the delay they impose on others, and traffic will fall to an efficient level. A newer line of work argues that this story is incomplete because it assumes commuters respond only to price and travel time. In field studies, many drivers interpret a fee not as a signal of scarcity but as a claim about legitimacy: if the city charges a price, then driving at peak hours can feel like a purchased right rather than a discouraged behavior. As a result, drivers who can afford the fee sometimes become less willing to shift travel times, even when their schedules are flexible.

The researchers do not conclude that pricing never works. Instead, they argue that the policy succeeds when it is paired with cues that preserve the sense that peak driving is exceptional, such as visible reinvestment in public transit, steeply tiered fees that communicate social priority, or exemptions framed as hardship relief rather than privileges. Their broader point is that transport policies operate not only through incentives but also through the meanings people attach to those incentives.

Which choice best states the central idea of the passage?