The MTA is adding additional trains for New Year’s Eve, and will enforce its annual ban on alcohol for commuter trains. 

The authority, the NYPD and the Times Square Alliance say people traveling into the city to celebrate should take public transportation, given annual road closures around much of Times Square and heightened traffic around Manhattan. 

Street closures will make crosstown car travel difficult between 42nd Street and 59th Street starting Saturday afternoon, according to the Alliance. 

The alcohol ban, which prohibits alcohol consumption on all Long Island Rail Road and Metro-North trains and platforms, goes into effect at noon. Saturday, Dec. 31, and extends for 24 hours. Police officers may write summonses, confiscate drinks or remove passengers from trains for violating the ban, the MTA said. 

The authority is slightly shifting its usual train schedules for the New Year’s Eve holiday. 

Nearly all train lines — the 1, 2, 3, 4, 5, 6, 7, C, D, L, N, Q and R trains, as well as the Midtown shuttle from Times Square to Grand Central — will have extra subway service. The remaining lines will run on a usual Saturday schedule. 

Northbound 1 trains will skip the 50th Street station, and N, Q, and R trains will skip the 49th Street station in both directions, starting at 11:45 a.m. Saturday. 

Trains will run on a Sunday schedule on New Year's Day and Monday, Jan. 2. 

The MTA is reducing buses through Friday, because most schools are closed for winter break. Bus lines that have both local and limited-stop services — including the M1, M4, Q4 and Q5 — will make local stops only. 

Buses will run on their typical schedules on Saturday and Sunday, and run on a Saturday schedule on Monday in all boroughs except Staten Island, which will be on a Sunday schedule. 

The LIRR and Metro-North will run on typical schedules this weekend, with some exceptions. 

The LIRR will have additional eastbound trains running on Friday afternoon, and extra Manhattan-bound trains going to Penn Station on Saturday evening. It will also have extra early morning eastbound trains on New Year’s Day.

The Metro-North will have extra outbound service from Grand Central Terminal from midnight to 5 a.m. on New Year’s Day. 

Additional updates, including delays and emergency construction work, will be available in the myMTA map.