Elected officials are demanding the city fill a gaping hole in Brooklyn’s protected bike network as cycling surges during the coronavirus — and newbie riders will need safety when all the cars return to the roads.

The Brooklyn Greenway Initiative — with 11 local officials — sent a letter this week urging the de Blasio administration to install jersey barriers along the greenway route running through Red Hook and across the Gowanus Canal. The missing section could be a key connector of Sunset Park, Red Hook, Gowanus, Carroll Gardens, Downtown Brooklyn and into Manhattan, according to the BGI letter, especially if the section across the canal on Hamilton Avenue is connected to Fourth Avenue.

And unlike other bike lane ideas in the city, this connector has already been engineered, planned and paid for — meaning that it doesn’t need anything but physical work.

“Capital funding is secured and construction was scheduled for groundbreaking this spring,” BGI Executive Director Terri Carta wrote. “But with a need to get our city moving again now — not to mention any potential delays with capital projects due to the pandemic — New Yorkers do not have time for the two-year capital construction.”

Borough President Eric Adams, Rep. Nydia Velazquez, Council Members Brad Lander and Carlos Menchaca and Assembly Members Jo Ann Simon and Kevin Ortiz are among the local lawmakers who signed on.

The Red Hook-to-Gowanus Greenway portion was expected to be completed in 2021 as part of the city’s Green Wave protected bike lane rollout, but the proposed design was also being looked at for flood-mitigation measures that would have required more than just simple jersey barriers or rejiggering some parking. Rather than wait for an opportunity when that kind of capital project can be worked on again, BGI and the letter’s co-signers are asking for jersey barriers to provide protection, and are also promising to “leverage political support and private sector resources” in order to get sturdy barriers for the bike lane.

The city has fast-tracked other protected bike lane proposals as part of its open streets program, but those 9 miles of bike lanes are being protected with plastic barrels. As it stands, riders who take the Brooklyn Greenway route through Red Hook and Gowanus are forced to contend with an unprotected stretch under the Gowanus Expressway, along Beard Street and then along most of Van Brunt Street.

A spokesperson for the DOT said the agency is reviewing the letter.