In announcing the plan, the de Blasio administration said that it was time to bring both bridges “into the 21st century and embrace the vision of a future without cars with a radical new plan.”
The new bike lanes are the result of decades of lobbying by cyclists and transportation advocates. “Converting car lanes into bike lanes on two of our most important bridges is a giant leap forward for New York City,” said Danny Harris, executive director of Transportation Alternatives, an advocacy group.
“We look forward to working with the de Blasio administration on this vital new project and other efforts to improve infrastructure for cyclists and pedestrians on bridges and streets across the five boroughs,” Mr. Harris added.
But State Assemblyman David I. Weprin, a Democrat from Queens who is running for city comptroller, said he was concerned that taking a lane away from cars on the two bridges would only make congestion worse once the city recovered from the pandemic and more people returned to work.
“There are still plenty of people who drive into Manhattan as well as small businesses who rely on those bridges,” Mr. Weprin said. “It certainly will be an issue once the city comes back.”
The plan for the new bike lanes comes amid an extraordinary surge in biking —the city had nearly 1.6 million bike riders before the pandemic, and cycling has exploded with trips at the city’s four East River bridges into Manhattan jumping by 55 percent in November compared with the same month in 2019.
The annual speech by the mayor has often become an opportunity to propose bold ideas like a sleek streetcar between Brooklyn and Queens, which Mr. de Blasio announced in 2016 with great fanfare but has not been built.
City officials said they want to build the two-way protected bike lane on the Brooklyn Bridge, which opened in 1883 and runs between Lower Manhattan and Brooklyn, by the end of this year.
The Queensboro Bridge, also known as the Ed Koch Queensboro Bridge, runs between Midtown Manhattan and Queens and opened in 1909.
The plan calls for converting the northern outer roadway of the Queensboro Bridge into a two-way bike lane. The southern outer roadway, which is currently used by Queens-bound cars, will be reconfigured as a pedestrian walkway. Construction should begin this year, but city officials said they did not know when it would be finished because of other construction already taking place on the bridge.
Cycling has expanded significantly across the Queensboro Bridge in particular during the pandemic, leading to more conflicts between cyclists and pedestrians, who currently share a two-way lane on the northern outer roadway.
City Councilmen Ben Kallos and Jimmy Van Bramer, whose districts include either end of the Queensboro Bridge, have fought for years for a separate bike lane. They have held several rallies and recently marched across the bridge during the pandemic.
“This news couldn’t have come sooner as more people rely on bikes during the pandemic,” Mr. Kallos said. “The single shared lane on the Queensboro Bridge has gotten more crowded and dangerous.”