Traffic Restrictions in NY, Paris, London Cut Pollution

Cities around the world trying to limit driving have faced objections — namely that the measures would limit personal freedom, cost too much, destroy commerce or have negligible effects on air quality.

Now the first data from these experiments in New York, London and Paris is trickling in. They offer some clues about whether cutting speed limits, charging traffic for entering a city center and penalizing drivers of the most polluting cars can reduce congestion and improve air quality, without causing too much disruption.

These lessons are helpful because cities, where problems with traffic and poor air quality are frequently more ...