BEAR, Del., (CBS) – Troopers are on scene of a crash involving an overturned school bus and tractor trailer Thursday night in Bear, Delaware.

The accident happened at about 10 p.m. at Summit Bridge Road and Howell School Road.

Delaware State Police say there were about 40 passengers, ages 18 to 22, on board the bus at the time of the crash.

Nine passengers were transported to Christiana Hospital.  Their conditions are unknown at this time.

Thirty passengers suffered bumps and bruises.

Police say none of the injuries appear to be life-threatening.

Drivers should expect road closures in the area of the crash.

Stay with for the latest on this developing story…