New and improved bike lanes are coming to the Bronx and Brooklyn this year, but some cycling advocates are concerned they won't come fast enough amid a spike in bicyclist deaths.

The New York City Department of Transportation says bicycle ridership in the city has reached a new all-time high, with more than a half-million bike riders on any given day. However, cycling deaths are also high, with 12 cyclists killed so far this year.

The DOT outlined the steps they are taking to expand bike lane infrastructure across the city.

“I want to assure New Yorkers that cycling in our city is a safe mode of transportation,” said DOT Commissioner Ydanis Rodriguez.

By the end of this year, the DOT expects to complete a number of protected bike lanes and expand community bike networks in underserved areas, including in the Bronx and Brooklyn. The department will also add protective barriers along 10 miles of bike lanes.

The DOT fell short of the 30 miles of protected bike lanes it was legally required to build last year. This year, they are mandated to build 50 miles of protected bike lanes.

The DOT says they are on track to meet that goal, but some advocates are skeptical.

“There's some deep concern that the city is not going to meet their 50 miles for this year, and we know that this is one of the deadliest years for cycling in New York City in the Vision Zero era,” said Juan Restrepo, a member of the nonprofit Transportation Alternatives.

New York City Council members introduced a bill at a hearing Monday that would speed up the process of building bike lanes.

“The DOT only has six or seven months of the year when the weather works to build new bike lanes. We need to expedite the amount of bike lanes that are constructed in NYC if we're going to hit the goals,” said NYC Council Member Lincoln Restler.

With summer around the corner, advocates are urging the city to act fast before another cyclist gets killed.

The DOT says it supports the bill.