Cape Town - No faults were found on the bus which overturned on the R44 near Stellenbosch on Tuesday, provincial traffic services confirmed.
Spokesperson Kenny Africa told News24 that the bus was inspected during an investigation into the incident.
“The vehicle was found to be in a very good state,” he said.
Bad weather conditions are believed to be the cause of the driver losing control of the bus transporting the Cloetesville High School pupils.
A total of 36 of the 57 pupils travelling on the bus were hospitalised for a range of injuries.
Paramedics found two children in a critical condition and another child was seriously injured.
Meanwhile, Africa said the cause of Wednesday morning's bus accident in Paarl, which left 15 people injured, is still under investigation.
According to ER24 paramedics, the bus veered off Swawelstert Road and ploughed into a vineyard.
“We found some of the occupants sitting outside the vehicle, while two patients were still inside,” said ER24 spokesperson Russel Meiring.
“On assessment, paramedics found that 15 people had sustained injuries ranging from minor to moderate. Paramedics treated the patients on scene and thereafter transported them to Mediclinic Paarl and Paarl Hospital for further observation.”
It is understood the bus was transporting people to work when the accident occurred.