JOHN YANG:

But first: Every day, millions of parents put their children on buses for the trip to school. Statistically, buses remain the safest way to make that trip. But fatal accidents do happen.

Just yesterday, an 11-year-old boy died in East Texas when the bus he was riding on collided with another vehicle and rolled over.

Special correspondent list Lisa Stark reports that a record number of states are trying to improve school bus safety, part of our weekly series, Making the Grade.