The MBTA has begun a yearlong pilot program of early morning bus service.
Some routes now start service as early as 3:20 a.m. Dozens of routes start before 5 a.m.
"This new transit option will serve workers who must start their day earlier than most," state Transportation Secretary Stephanie Pollack said in a statement. "Other commuters and city residents depend upon these essential workers and the MBTA’s ability to get them to their work places safely and on time."
The changes include additional service on existing routes during predawn hours, and some bus routes are being extended during the early morning to bring commuters more directly to downtown Boston.
"What we're trying to do is establish these connections from neighborhood to neighborhood in times when people may need service and we're not operating service earlier," said the T's deputy chief operating officer, Jessica Casey.
Here's the MBTA's page on all the route changes.