NEW YORK (CBSNewYork) – The long-awaited L train slowdown is now underway.

While it’s not a full shutdown, train service has been drastically reduced on nights and weekends.

If you’re commuting between Brooklyn and Manhattan over the next 15-18 months, you’re going to need a backup plan for getting around New York.

Here’s CBS New York’s guide to avoiding the L train slowdown on mass transit:

What’s affected?

  • The MTA says it will have exactly the same service during weekdays and rush hours.
  • Trains will run every 20 minutes in both directions between Brooklyn and Manhattan during weeknights and weekends.
  • Train will run every 10 minutes in both directions within Brooklyn on weeknights from 10 p.m. to 1:30 a.m. and on weekends from 6 a.m. to 1:30 a.m.

What are the subway options?

  • M train – MTA will extend hours of normal weeknight and weekend service into Manhattan, between 10 p.m. and 1:30 a.m. up to 96 Street-2nd Avenue on the Q , instead of to Queens Blvd.
  • G train – Five additional trains will run between 8:30 p.m. and 1:30 a.m. on weeknights. On weekends, trains will run every eight minutes instead of every 10 minutes during the day.
  • 7 train – Five additional trains will run between 8:30 p.m. and midnight on weeknights. On weekends trains will continue to run normally.

What are the bus options?

  • MTA is planning additional M14A bus service to connect to the affected subway lines.
  • On weeknights, M14A buses will run every four to five minutes between 8 p.m. and midnight in both directions across 14th Street – connecting to the M train at 6th Avenue.
  • The M14A will connect to the Delancey-Essex J/M Station every seven to 10 minutes.
  • On weekends, the M14A/D buses will run every three to five minutes for most of the day along 14th Street.

New Williamsburg bus link

  • The Williamsburg Link will operate on two routes, the clockwise B-92 and one counterclockwise B-91.
  • The buses will connect the Bedford Avenue L train, Metropolitan Avenue-Lorimer Street G and L trains, Marcy Avenue J and M trains, and Hewes Street J and M train.

For more information on the L train slowdown and MTA routes around Brooklyn and Manhattan, click here.