FILE: Education Secretary Arne Duncan (Jay LaPrete/AP)

As another school-year begins, bleary-eyed teenagers are again waiting at bus stops in Montgomery County and other parts of the region — and the campaign to push back high school start times is returning to the spotlight.

Supporters of local and national efforts to get teenagers more sleep by shifting high school schedules say they were thrilled when Education Secretary Arne Duncan tweeted his support for the idea last week, days before school’s opening in Montgomery.

“Common sense to improve student achievement that too few have implemented: let teens sleep more, start school later,” Duncan tweeted.

Later, when a follower responded that later start times had worked well for a Wyoming school system, Duncan tweeted again: “Great to hear it’s working!”

The nod from Duncan has been big news among many supporters of the change — which is being considered in the Washington region by school systems including those in Montgomery, Fairfax and Anne Arundel counties.

“It’s been retweeted like crazy,” said Heather Macintosh, a parent who helped launch a petition for later start times in Anne Arundel and has been involved in efforts nationally.

In Montgomery, the opening bells of high school ring at 7:25 a.m. In Fairfax, the school day begins at 7:20 a.m. Anne Arundel opens at 7:17 a.m. Many teenagers head to bus stops in the 6 o’clock hour.

High schools open later in both Arlington and Loudoun counties.

Terra Ziporyn Snider, executive director of the national group Start School Later, said activists are optimistic about the effect of Duncan’s words.

“It really does give credibility,” she said. “We’re very pleased.”

In Montgomery, the tweet comes a month before a special work group is scheduled to report its findings on the issue to the Montgomery County Board of Education.

Parent Mandi Mader, who launched a petition drive in Montgomery last October, took heart from the high-profile attention. “I think it’s part of a sign that the movement is growing here and the research is strong,” she said.