Tammy Stevens drifted off while traveling down Covered Bridge Road near Loop Road, troopers said. The bus hit five mailboxes and a car before crossing over a ditch and coming to a stop in a field.
No students were on the bus. Stevens had just dropped off students from Riverwood Middle and Elementary schools.
The driver of the car Stevens hit was not seriously injured.
Stevens, who was not hurt, is facing reckless driving charges, troopers said.