A school bus (searchoverturned on a highway Monday morning, injuring the driver and many of the 26 children aboard.

The bus was carrying St. Louis (searchstudents, ages 6 to 11, to a school in suburban Chesterfield as part of a voluntary desegregation program.

The accident happened on Interstate 64 about 10 miles outside the city limits. The bus flipped over after the driver crested a hill and found traffic was backed up. She tried to stop, but the bus skidded about 100 feet on its side, the Highway Patrol said.

No other vehicles were hit. Children were able to get out through a back door and through the front, where the impact knocked out the windshield.

The driver, Linda Gilley, 50, of St. Louis, and an 8-year-old were seriously hurt, and both underwent surgery late Monday. A 10-year-old, originally said to be in serious condition, was treated and released, a hospital spokesman said.

Hospital officials said most of the injuries were bumps and bruises.