At Montgomery County high schools, the first bells ring in the 7 o'clock hour. A new petition asks for later times: after 8:15 a.m. (Susan Biddle/For The Washington Post)

Montgomery County’s schools chief said Tuesday that he will form a work group to study later start times at public high schools, a move that comes two months after county parents launched a petition calling for opening bells at 8:15 a.m. or later.

Superintendent Joshua P. Starr made the unexpected announcement at a county Board of Education meeting after parents delivered two thick binders containing 950 pages and more than 10,000 signatures supporting later high school start times.

“I’m thrilled he was able to take this feedback and listen to the community,” said Mandi Mader, a Garrett Park parent who created the online petition in October. “I don’t want it to be studied to death,” she added, “but I am hopeful and optimistic.”

Starr said the work group will examine Montgomery studies from the late 1990s and will look into the latest research and the experiences of other school systems. In Montgomery, the opening bell of high school rings at 7:25 a.m. In Loudoun and Arlington counties, high schools start later.

Describing the suggested change as a “complex issue,” Starr said the work group will assess a range of potential effects and seek responses from across the school community. A report is expected in the spring.

Critics of a proposed change say it would be costly and complex, as school buses often stagger their routes, picking up high schoolers earliest, followed by middle schoolers and children in elementary grades. Supporters of a later school day cite an array of benefits to teens who get more sleep: stronger academic performance, better attendance, and fewer car crashes and mental health problems.

Michael Rubinstein, father of a student at James Hubert Blake High School, said he was heartened by the formation of the work group.

Still, he said, “my concern is that this could very easily go down a bureaucratic rat hole.” Rubinstein said school leaders should recognize that “we’re serious about this and we’re not going to go away until they make the change.”

Three dozen supporters of the petition turned out for the board meeting, waving posters and wearing T-shirts calling for later start times.

In comments to the board, Mader, who founded the Montgomery chapter of the national group Start School Later, said the signatures reflect “a broad and deep concern about our children’s education, wellness and stress level.”

Judith A. Owens, director of sleep medicine at Children’s National Medical Center, said a recent Brookings Institution report had identified delaying school start times as one of the three most potentially cost-effective ways to boost academic achievement.

Mike Kramer, a 16-year-old Walter Johnson High School junior who started a Facebook page about the issue last year, told the board that many teens fall asleep during the first two periods of the day — and would have to be asleep by 8:30 p.m. to get a full night’s rest. “The idea of going to bed at this time is unimaginable to most teenagers,” Kramer said.

Critics of the later start times did not speak at the meeting. In the past, cost has been a major focus, and some have worried that it would interfere with teenagers’ child-care duties, sports and activities, and after-school jobs.

“It’s not that we’re not interested,” Board of Education member Patricia O’Neill (Bethesda-Chevy Chase) said in the board’s brief discussion Tuesday. “Everything is more complicated than you think.”

In Anne Arundel County, parents have collected nearly 2,000 signatures on a similar online petition, calling for a new policy to require that all students, regardless of age, start at 8 a.m. or later, with no one boarding a bus before 7 a.m. Anne Arundel high schools start at 7:17 a.m.

“Frankly, our children are sleepwalking through their early classes,” said Joanna Conti, head of the Parents Advocacy Network in Anne Arundel, which is urging people to sign a petition started by that county’s chapter of Start School Later.

“It’s doubtful they’re learning that much,” she said.

Fairfax County school leaders voted in April to establish a goal of later start times and are hiring a consultant to come up with a “blueprint” for change. High schools in Fairfax start at 7:20 a.m.

“It would be great if we could get this fixed on both sides of the river,” said Fairfax School Board member Sandy Evans (Mason).