As in years past, BART will extend its New Year's Eve service until 3 a.m. If you're not done celebrating the arrival of 2015 by then, have a great Uber.
BART NYE will run a normal but extended weekday evening service schedule 3 am, with trains running every 20 minutes after midnight. Extra trains will be standing by in downtown San Francisco after the fireworks show.
And, to hypothetically relieve congestion and maybe actually play a cruel game on us all, "skip-stop" will be back. Beginning at 8 p.m. at the busiest stations (Embarcadero, Montgomery, and West Oakland stops) BART will use this special train pattern into and out of San Francisco. Have a look and make your plan now, because you may be in no condition to do so come that evening.
On New Year’s Day, while BART is laboring over a New Year's resolution for itself (I can think of several), the service will operate a Holiday/Sunday timetable starting as usual at 8 a.m.