An aerial view of Capsouto Park. The DOT proposed putting a bike lane on a cobblestone part of Varick Street that lines the park. View Full Caption DOT

TRIBECA — The Department of Transportation wants to install a new bike lane in TriBeCa — on a sidewalk.

The proposed lane would run along part of a cobblestone block of Varick Street, just south of Canal Street, according to Hayes Lord, the director of the DOT’s bike program, who gave a presentation to Community Board 1’s TriBeCa committee Wednesday night.

The unusual sidewalk bike lane — an exception to the city's sidewalk cycling ban — is designed to combat the perils of biking on uneven cobblestone, Lord said.

The lane would also allow the city to create a continuous bike path down Varick Street, which wouldn't be possible on the cobblestones because the paint marking the lane "will quickly disappear," Lord said.

The sidewalk proposal is just one part of the DOT’s broader plan to create new bike lanes from TriBeCa up to Union Square, which officials hope to launch in August.

Below Canal Street, the new paths, which wouldn’t take away any parking spaces, would run on Church Street, West Broadway, Varick Street and Sixth Avenue, Lord said.

The lanes north of Canal are slated to run along West Broadway from Canal Street to Houston Streets, LaGuardia Place from Houston Street to Washington Square, then heading to Fifth Avenue. The paths will also run on Broome Street from West Broadway to Varick Street, and Varick Street from Broome Street to Canal Street.

While the committee supported the new, larger proposal for bike lanes, the sidewalk lane was vehemently opposed by community board members.

“Bike lanes make everyone safer — they’re great,” said CB1 member Mark Costello. “But, no, definitely not on a sidewalk. That makes no sense and it’s not going to work — it’s not safe for pedestrians.

“The DOT just has to come up with a better idea. Plain and simple.”

The sidewalk lane particularly rattled CB1 members because it runs along a piece of Albert Capsouto Park, a triangular green space that sits in the busy intersection of Canal, Laight and Varick streets.

The park was renamed for a CB1 member who died in 2010 and had led the push to create a park — and sidewalks — in the traffic-heavy area.

"We want to protect the park and the sidewalks," Costello said. "We can't have a bike lane there."

But one TriBeCa resident, avid biker Charles Komanoff, pointed out that cyclists often use the sidewalk anyway to avoid the cobblestones — and that a demarcated lane might actually boost safety, not hinder it.

The board, however, was not ready to roll with that idea.

Hayes told CB1 that the DOT wouldn’t move forward without the board's support, so he’d have to "take the input back to the DOT."

"We need that piece of Varick for the larger plan," Hayes said. "But we want the community's support."