At about 7:30 this morning, the Caddo Sheriff's Office was called out to an accident in the 5400 block of Harper Road.  When they arrived, they found out that a Caddo school bus had flipped.  Sheriff's Spokeswoman Cindy Chadwick says the driver of bus #81 was picking up kids to take them to Summerfield Elementary.  She was headed south on Harper, when she ran off the road, overcorrected and hit an embankment, flipping the bus on its passenger's side.  There were four children on the bus.  They were taken to Willis-Knighton South with minor injuries.  Chadwick says, though the accident is still under investigation, the bus driver is expected to be charged in connection with prescription drugs she'd taken.  We'll bring you updates as we get them.