Updated, 9:30 a.m.

Good morning on this misty Tuesday.

After nearly a century of planning, the Second Avenue subway line opened this weekend. Today, it’s reaching another milestone: the first real morning commute.

(The Metropolitan Transportation Authority has shared this handy guide for commuters, and here are maps specific to the 96th Street, 86th Street and 63rd Street stations.)

For many on the Upper East Side, today is the first of many shorter trips to work. Residents we spoke to said they could save anywhere from five minutes to more than an hour each day.

So what is a time-starved New Yorker to do with those precious extra minutes in the morning?

“Sleep, obviously” said Emily Kuo, 33, who will save five or 10 minutes in the morning. “One more snooze.’’