New York is the latest city to contemplate congestion pricing as a way to deal with traffic problems. This strategy, which requires motorists to pay fees for driving into city centers during busy periods, is a rarity in urban public policy: a measure that works and is cost-effective.

Properly used, congestion pricing can ease traffic, speed up travel times, reduce pollution and provide funds for public transport and infrastructure investments. The details matter, including the size and timing of charges and the area that they cover. Congestion charges also raises equity issues, since rich people are best able to move closer to work or change their schedules to avoid the steepest costs.

But the key point is that this approach has succeeded in cities including London, Singapore and Stockholm. For scholars like me who focus on urban issues, serious discussion of congestion pricing in New York City is welcome news.

Cities concentrate people close together for good economic reasons. Clustering activities allows transfers of information, knowledge and skills. At their best, cities create deep pools of labor, large markets of consumers and savings in the provision of public goods such as mass transit and trash collection. Planners should be encouraging cities to become bigger and more dense if we want to improve economic performance.

But growing concentration also imposes costs, and one of the largest is traffic congestion. Costs multiply when we factor in use of motor vehicles on public roads. Drivers spend valuable time sitting idly in traffic jams, while noise, accidents and pollution impose heavy burdens on city resident

Read more about traffic congestion in cities by John Rennie Short at The Conversation