Implementation of most of the Fourth Avenue redesign in Sunset Park has been delayed to accommodate MTA tunnel repairs, pushing back the construction of curbside protected bike lanes until 2019 or later. Only about 10 blocks of the redesign will be built this year, and even that is contingent on the MTA’s progress, according to DOT.

The original timetable had called for protected bike lanes between 65th Street and 38th Street this year, with a subsequent segment between 38th Street and Atlantic Avenue coming in 2019. A second phase of the project was slated to build those changes out with a top-to-bottom street reconstruction starting this fall.

Now the timetable is much murkier.

DOT plans to proceed this summer with only four blocks of the redesign, between 64th Street and 60th Street, then another six blocks, between 60th Street and 54th Street, in “late fall.”

Although the first phase of the project calls only for temporary materials, the MTA’s underground work will disrupt the street surface, occupying a southbound car lane, said Community Board 7 District Manager Jeremy Laufer.

DOT did not provide a timetable for the redesign north of 54th Street and said all work on Fourth Avenue is contingent on MTA construction.

“We are following this construction very closely and are adjusting our implementation schedule in line with the planned work,” DOT said in a statement. “As each phase of subway construction is completed, we will follow behind with the bike lanes. This is all subject to change as MTA updates their plans.”

The Fourth Avenue redesign is the most significant street safety project in the pipeline for Brooklyn. CB 7 endorsed the project in January.

When complete, the redesigned Fourth Avenue will provide safer pedestrian crossings and the first convenient, low-stress north-south bike connection through the neighborhoods of western Brooklyn.