Drivers in the state's fleet of 5,000 public school buses would be forbidden to text message or talk on cell phones while transporting students under a proposal before the House Transportation Subcommittee today.

The proposal calls for signs to be placed on buses that would encourage students to turn in their driver if they see him or her using a cell phone while operating a school bus or failing to wear a seat belt.

The measure targeting bus drivers is an amendment to a broader driver-safety bill that would ban all texting and hand-held cell phone use by motorists in South Carolina. The bill and amendments will be taken up today.

"School bus drivers have our most precious cargo, and I want them to totally concentrate on what they're doing," said Rep. Joe Daning, R-Goose Creek, who is proposing the amendment.