Nothing in particular pushed Andrea Keefer over the edge.

Rather, it was the daily parade of cleavage and bare midriffs, barely there miniskirts and micro-shorts that convinced the former Francis Scott Key High School Student Government Association president and other student leaders in the county that Carroll County's public schools needed a stricter dress code.

"Once it gets really hot, people wear everything other than their bathing suits to school," said Keefer, 17, who graduated this month from Key and will start classes this fall at Mary Washington College in Fredericksburg, Va. "When you see people wearing things like that to school, you know they're not there to get an education. It's disrespectful."

The Carroll school board is poised to adopt the dress code Keefer wrote - one that is far stricter than anything most administrators would have suggested and one of the most stringent in the region - at this afternoon's board meeting.

Under the new policy, hats, visors and bandanas are not allowed. Shirts must cover the entire back and must hit the top of students' pants, skirts or shorts, pre-empting Britney Spears imitators from baring their bellybuttons. Skirts and shorts must be a modest length, resting midthigh or lower when a girl is seated.

For school officials, the biggest surprise about the new dress code might be that it was proposed by students.

"For the general public out there, they'll be happy to know that our youth are a little bit more conservative than some people give you credit for," school board vice president Susan Holt told Keefer after her presentation to the board last month.

But Caroline Clauss-Ehlers, a professor at Rutgers' Graduate School of Education who has a private psychotherapy practice in New York, said it is not as uncommon as adults might think for students to voluntarily tighten dress codes.

She has talked with teen-agers who wanted school uniforms - and even a schoolwide prom dress - to ease tensions between poor and wealthy students, eliminate the distraction of skimpy outfits and minimize differences in the way teachers interact with neatly dressed students and those sporting baggy pants and hip-hop-inspired outfits.

"It's something that would surprise most adults because they tend to view adolescents as wanting a lot of freedoms and wanting to do their own thing in a time of rebellion," Clauss-Ehlers said. "But, in fact, adolescents need a lot of support, they need stability, they need feedback and they need structure. When you look at it this way, it's not surprising that kids are talking about this."

Keefer might be in favor of a stricter dress code, but she is not a prissy goody-two-shoes.

Bad with curfews and known among friends for her spunk and quirky style, she mixed easily among all types at Key. She also is no dowdy dresser.

"I have two different wardrobes - one for school and one for the weekends and summer," she said. "I'd be embarrassed if I ran into my principal wearing what I wear on the boardwalk."

The task of tackling the county's dress code took Keefer and her fellow high school students into tricky territory, as they struggled to set rules without infringing on students' desire to express themselves through their clothing.

The county student government's general assembly - 25 students from each high school - devoted two meetings to the subject while the executive board debated late into the night several times during the past school year.

They pondered appropriate lengths for shorts, skirts and skorts - the shorts-skirt combination that older generations knew as culottes. They discussed whether violators should be publicly humiliated and forced to wear an ugly cover-up T-shirt. In the end, they decided not to set guidelines for piercings and dyed hair, concluding "that was one of those things that you just have to let kids be kids with," Keefer said. They also declined to set specific restrictions on shorts, requiring only that they not be "excessively short."

But the superintendent's dress code committee decided to apply the same mid-thigh-when-seated rule to shorts that the students had written for skirts. That committee, which included Keefer as the student representative, was appointed last month to study the students' recommendations and forward a proposal to the board.

School board members acknowledge that the provision might have the unintended effect of doing away with shorts in school, considering designers' proclivity for producing short shorts for young women. But board President Susan W. Krebs said she's confident students will follow the new policy.

"I think people will respect it as long as they're not caught off-guard and embarrassed wearing something they've always been allowed to wear," she said. "But three-quarters of the kids who wear shorts to school will not be able to wear those shorts this fall and we don't want all our kids sent home on the first day."

The new provision for shorts is the only aspect of the final dress code with which Keefer does not agree.

"I don't think it's going to be possible for people to find shorts of that length. Plus, it will be really difficult to enforce," she said. "It does make sense to me, because if we say skirts and skorts can only be so long, it's reasonable to say shorts should be that length. But I know that 95 percent of girls who wear shorts to school will be in violation of the dress code."

The school board is scheduled to vote on the policy at its 1 p.m. meeting today.