The Knoxville Police Department is investigating what caused a Knox County school bus to crash on I-40 Thursday afternoon.

Both vehicles were traveling west on I-40 around 2:30 p.m. when the bus, which was preparing to take the Hall of Fame exit, suddenly veered back onto the interstate and across all lanes of traffic, according to Knoxville Police Department spokesman Darrell DeBusk.

ORIGINAL STORY: School bus crashes into truck, forcing it over I-40 median

The bus hit the pickup truck which was traveling in the far left lane and forced it into the median wall, then up and over the wall and into the eastbound lanes.

The driver of the bus has been identified as Sharon Lynn Emery, 67, of Knoxville. Frank Tumazeh, 40, of Knoxville was driving the pickup, according to KPD.

Both drivers were taken to UT Medical Center for treatment, but their injuries didn't appear life threatening. There were no children on the bus, which is owned by Lynch Bus Lines.