Brooklyn Bridge bicycle and pedestrian path on Tillary and Adams streets in downtown Brooklyn.

Some of the busiest streets in Brooklyn will be getting new bike lanes this year.

The city will be rolling out 30 miles of new “protected” lanes, with at least 10 miles to be built in Brooklyn after the borough saw an alarming surge in cycling deaths last year, officials announced Wednesday.

“Last year was tremendously difficult in terms of cycling here in Brooklyn. We saw a terrible spate of cyclist fatalities,” said Transportation Commissioner Polly Trottenberg at a downtown Brooklyn news conference.

Protected bike lanes — which are typically separated from traffic by parked cars or bollards — are planned for eight streets:

Fourth Avenue in Park Slope/Gowanus

Flatbush Avenue through Prospect Park

Ft. Hamilton Parkway in Windsor Terrace

Franklin Street in Greenpoint

Meeker Avenue in Williamsburg/Greenpoint

Navy Street in Downtown Brooklyn

Remsen Avenue in Canarsie

Smith Street in Downtown Brooklyn

Some of those will extend existing lanes — including on Fourth Avenue and Meeker Avenue — while others will be completely new.

Design details for the lanes are still being hashed out — but making way for the new bike space in Brooklyn will require the removal of “fewer than 300” parking spaces, a DOT spokesman said.

It’s not yet clear how many miles of car travel lanes could also be removed, though the spokesman insisted that some projects won’t require taking any space from car traffic.

There were 29 cycling deaths on city streets last year — compared to just 10 in 2018 — with 17 of them taking place in Brooklyn. Overall traffic fatalities also rose — from 203 in 2018 to 220 in 2019.

The bike lane announcement came ahead of a City Council hearing Wednesday where elected officials grilled Trottenberg and others on the uptick in deaths.

“The number of vehicle crashes across the city must be treated as an emergency,” said Councilman Ydanis Rodriguez (D-Manhattan). “This cannot continue happening under our watch.”

Trottenberg reiterated her belief that the increase is tied to a growing number of SUVs and other trucks on the roads and said there would be a focus on trucking safety this year.

She also noted that police counted deaths of e-bike riders among bicycle deaths last year, where in previous years they’d been classified as motorcycle deaths — accounting for five of the additional fatalities.

The new lanes are part of the city’s $58.4 million “Green Wave” plan to build out bike lanes and retime traffic lights to benefit cyclists.

The city has on average built about 23 miles of new lanes per year since 2015, compared to an average of about 5.8 miles in the five years prior.

City data released last fall shows that the number of New Yorkers who regularly ride a bicycle dropped 5 percent in the last two years.