"Obviously, if something happened to the driver, obviously, you'd want to make sure that the student on the bus would be able to get out," Johnson said.

Channel 4 safety expert Ken Jefferson said transportation companies should consider having attendants on school buses.

"I think that the bus companies need to look at having some type of adult monitor that sits on the bus -- not engaging the students, just to monitor the behavior of the kids so something like this can't happen," Jefferson said.

After more than three hours of investigation by Jacksonville Beach and Duval County School Board police, the bus was towed away and the westbound lanes of the bridge reopened.