New York City's transportation commissioner isn't backing down from her full-throated support of more bike lanes and amenities for pedestrians.

Speaking at a conference for bicyclists in Washington, D.C., Janette Sadik-Khan said that to succeed, cities of the future will have to be able to move people more efficiently and use less energy by encouraging biking, transit use and walking.

"We're starting to see real cycling systems in American cities," she said. "In New York, we have added 250 miles of on-street bike lanes since 2006."

The transportation commissioner has been sharply criticized recently, with some residents of Park Slope, Brooklyn, filing suit this week to remove a bike lane and having a much-discussed profile in The New York Times published in which she was called "brusque." And a New Yorker writer described her as the head of "a small faddist minority intent on foisting its bipedalist views on a disinterested or actively reluctant populace."

But Sadik-Khan is continuing to make the case that the economic and cultural future belongs to cities that wring transportation efficiencies out of moving more people above-ground by bus, bike and foot.

She listed famous streets in the U.S. that now have bike lanes and more space for pedestrians — from Market Street in Portland to Commonwealth Avenue in Boston. She praised Barcelona for throwing "infrastructure parties" — transit projects and urban upgrades completed in preparation for large events like the Olympics. And to the approval of the room, she talked up the pedestrian plaza her department created in Times Square.

"You can see this on Broadway, in my town, which is now the Great Green Way," she said, "and more is coming. I don’t know if you heard that just last week Mayor Villaraigosa of Los Angeles talked about plans for a 1,700-mile bike network in Los Angeles. I think that’s really extraordinary."

All of this is proof, she said, of a global competition by cities to innovate with their transportation systems.

"City leaders — mayors, certainly — understand this is an economic development strategy," she said. "If we are going to attract the best and the brightest to our cities, we have to make these cities work."

She said that means urban planners are looking at the competition and asking: "Who can be the greenest? Who's got the next bike share program? Who's got the coolest new bus rapid transit line?"

But she said urban development is not solely competitive. Together with transportation officials around the U.S., she launched an online Urban Bikeway Design Guide that cities can use as an engineering template to construct even more bike lanes. The group will be lobbying the Federal Highway Administration to recognize the guidelines as national standards, she added, making it easier to install bike lanes around the country.