By JIM SALTER ,  Associated Press

ST. LOUIS (AP) — The principal of a suburban St. Louis grade school expressed "huge relief" Thursday after 13 students escaped serious injury in a harrowing school bus accident.
The children and bus driver were hurt Thursday morning when the bus swerved to avoid an accident on Interstate 44, drove over a guardrail and down a steep embankment.
As bad as it looked, the bus driver was able to keep the vehicle from tipping over as it rambled down a bumpy, grassy ravine, ending up against trees and bushes. The driver is hospitalized with moderate injuries but is expected to make a full recovery, Missouri State Highway Patrol Sgt. Al Nothum said.
The kids suffered scrapes and bruises, including one boy who was ejected through an emergency door. All were taken to St. Louis Children's Hospital, and none will require an overnight stay, pediatrician Kimberly Quayle said at a news conference. Hospital officials initially said there were 14 students on the bus, but later revised that to 13.
The students are St. Louis children who participate in the region's voluntary desegregation program. They were on their way to Hanna Woods Elementary School in the St. Louis County town of Manchester, Missouri. The program allows city students to attend classes in more affluent county districts at no cost.
"Definitely a huge relief as we came here and found out that all the kids will leave with their families today," principal Patrick Shelton said at the hospital.
Nothum said a car passed a pickup truck around 8 a.m. and was in the far left lane when it struck the concrete median and spun out of control on pavement wet from rain.
He said it wasn't clear if the car struck the bus, but the bus driver swerved to avoid it. The bus topped the guardrail and went about 15 feet (5 meters) down the embankment. Several passing motorists stopped to help, along with people from a nearby neighborhood.
Nothum said the bus driver's ability to keep the bus upright may have saved lives.
"If it would have flipped over there would have been a lot more injuries or even worse," Nothum said.