The bus driver pulled over near the Lonestar Steakhouse in the 6600-block of Knightdale Boulevard, which is just east of Interstate 540, when the driver and students noticed steam or smoke coming from underneath the bus.
The 30 to 35 students onboard were evacuated and appoximately 14 students complained of a burning sensation on their feet.
"Steaming hot water went on the floor," said student Lauren West. "We couldn't see and it smelled really bad and people were jumping out of the windows."
School officials told ABC11 that those students were evaluated by medics at the scene. No one was taken to the hospital.
The bus involved was number 690 from Wake County Schools. It was carrying students from Wendell Middle School.
A spokesman for Wake County Public Schools said a broken belt in the engine to the rear of the vehicle is to blame. Last week, the bus driver had complained that the vehicle was overheating. The school system said mechanics inspected the bus, but didn't find any problems.
"I think they can say with confidence that any time they go through a maintenance check and they go through those inspection they're ensuring a bus is absolutely safe before they'll put it on the road with students," said spokesman Mike Charbonneau.