Howard County Police are investigating a vehicle collision in which a school bus overturned.
Of the 19 Hammond Middle School students on the bus, two boys and two girls, ages 11-14 were taken to the hospital for a checkup.
The bus left the roadway for an unknown reason and no other vehicles were involved.
Police say there were no indications of driver impairment.
None of the injuries are life-threatening at this time.
The cause of the collision remains under investigation.