Interesting New York Times article today about how New York has grown its economy and population without growing its traffic. Their secret weapon: public transit.

As the city’s economy soared and its population grew between 2003 and 2007, something unusual was happening on the streets and in the subway tunnels.

All those tens of thousands of new jobs and residents meant that more people were moving around the city, going to work, going shopping, visiting friends. And yet, according to a new city study, the volume of traffic on the streets and highways remained largely unchanged. Instead, virtually the entire increase in New Yorkers’ means of transportation during those robust years occurred in mass transit, with a surge in subway, bus and commuter rail riders.

“What you see is that for the first time since at least World War II, all of the growth in travel in the city has been absorbed by non-auto modes, primarily by mass transit,” said Bruce Schaller, New York’s deputy transportation commissioner for planning and sustainability, who wrote the study to be released on Monday.

But not all is peaches and cream:

[T]he system faces its worst finacial crisis in more than two decades, with officials proposing raising fares and cutting service, measures which threaten to unravel the system’s gains and hamper its ability to carry riders when the economy recovers.