Drivers who use handheld cellphones in some school zones soon could face fines.

Gov. Bobby Jindal has signed a measure by Rep. Jeff Thompson that calls for penalties against drivers who use handheld cellphones in school zones that choose to post a sign saying such use is prohibited.

Fines will be up to $175 for a first violation and up to $500 for additional violations.

Originally, the ban would have been statewide, but senators made it optional for school districts because of signage costs.

Thompson, a Republican from Bossier City, pushed the bill as a way to make school zones safer for children.

Jindal’s office announced last week that the governor has signed it into law. The new law takes effect Aug. 1.