An estimated 3,300 Hawaii students who ride in small public school buses will need to buckle up with a combined shoulder and lap seat belt under federal safety regulations announced yesterday.

The rules will be phased in during the next few years and also will mandate all of the new yellow buses, including larger ones that transport some 37,000 isle students to public schools, to have higher seats. The government says increasing seat heights to 24 inches from 20 inches will help prevent taller and heavier children from being thrown over padded seats in a crash and injuring themselves and others in front.

The new requirements were drafted following the deaths of four Alabama students on a school bus that nose-dived off an overpass on Nov. 20, 2006. They also come about six months after a school bus carrying 25 members of Kahuku High's girls water polo team flipped onto its side after the driver swerved to avoid a car on Kamehameha Highway. All passengers were taken to hospitals, but there were no deaths.

The combination shoulder and lap seat belts will have to be installed only in new buses weighing 5 tons or less, and the requirement will not take effect until 2011. These smaller school buses already need to have lap belts but not the safer, harness-style belts.

U.S. Transportation Secretary Mary Peters said she stopped short of requiring seat belts for larger buses because that could limit the number of children who can squeeze into seats, forcing some children to walk or be driven to school in other vehicles - which are not as safe as school buses.

Historically, calls to install the restraints have failed, in Hawaii and nationally, largely because of the cost to retrofit school buses, which already have stricter safety standards than other vehicles, such as padded seats to protect students during an impact. Out of more than 800 students killed each year going to and from school, about 15 were riding school buses, according to the National Association of State Directors of Pupil Transportation Services, which estimates some 25 million children rely on the buses.

Schools Assistant Superintendent Randy Moore said the state Department of Education might have to absorb some of the costs bus companies will incur to comply with the new guidelines.

Louis Gomes, president of Ground Transport Inc., which has bus contracts with the Education Department, as well as private schools such as 'Iolani, Mid-Pacific Institute, Maryknoll and Punahou, said it is too early to say how much his expenses could rise.

“;When buses are ordered, we would go to the dealer, and then the manufacturer would have to build the buses accordingly,”; he said. “;We would have to factor all that into our costs.”;

The Transportation Department estimates it will cost about $6.1 million a year to equip new, smaller buses with the three-way seat belts and higher seat backs, and $3.6 million a year to equip new, larger buses with higher seat backs.

The Hawaii Education Department spends $44.2 million annually to have a dozen companies transport about 22 percent of the nearly 180,000 isle public school students in 530 of the big buses and 290 smaller buses. The smaller buses are used almost exclusively for special-education students, some who need to be picked up at home, Moore said.

Board of Education Chairwoman Donna Ikeda, who supports the seat belts, praised the new federal safety controls.

“;That's great,”; she said. “;I think kids' safety comes first.”;