Yesterday, the Department of City Planning asked experts from around the country how to make a more sustainable zoning code. Their response? Scrap parking minimums.

The recommendation came during a major conference held yesterday by DCP and Harvard University. Top urban thinkers from around the country gathered to discuss how the zoning code can make the city more globally competitive, socially equitable, architecturally significant and environmentally sustainable (for a good recap of the conference, check out the Architect's Newspaper live blog).

When the conversation turned to suggestions for building a sustainable city, both panelists raised the issue of parking minimums.

"Parking is one of the biggest things," said Harriet Tregoning, the director of D.C.'s Office of Planning, as she articulated how zoning can make cities greener. "[Washington has] removed our minimums for most buildings in the downtown and near transit."

That policy puts D.C. significantly ahead of New York City. While the Manhattan core -- admittedly a more populated area than all of Washington -- has parking maximums in place, most of the city is still governed by parking minimums, even areas right on top of subway stations.

DCP is considering reducing parking minimums in the "inner ring" of neighborhoods around the Manhattan core, but not eliminating them. So building space for car storage will still be mandatory even in highly walkable and transit-rich neighborhoods like Harlem, while dense, transit-rich areas just a little further removed from downtown, like Washington Heights, may not see any reforms at all.

Tregoning said that D.C. opted to eliminate parking minimums entirely in response to "hard experience." Having cut parking requirements in half, she explained, "we still had only half the parking used."

D.C. is also replacing parking minimums with maximums in many places. The city received significant pushback from the public and developers, Tregoning admitted, so they developed a compromise. "You can build more than the maximums, but the first floor of that building has to be level and convertible so that if we're right and you're wrong, it can be something useful."

Tregoning went so far as to offer herself as a resource to New York City should it decide to pursue parking reform. "We should think of ourselves as a band of brothers," she said. "Why don't we emulate success?"

The private sector, too, argued that removing parking minimums is critical to allowing sustainable growth. Developer Jonathan Rose noted that he applied for a mayoral override of the parking requirements for Via Verde, the green affordable housing project in the South Bronx that has received nothing but rave reviews. "We decided that affordable housing three blocks from transit in a great retail district didn't need parking," said Rose.

The goal of yesterday's conference was to develop big ideas for the city moving forward. "Today's discussion will really enable us to mark out new strategies for the city, for this administration and the next administration to come," said DCP Director Amanda Burden at the event's close. Will Burden listen to her invited guests and move boldly on parking reform?