Knoxville — Put your phone down when you're driving through a school zone.

It's the law -- and area law enforcement agencies will ticket you if you fail to obey.

On Friday, the Knoxville Police Department, Knox County Sheriff's Office and Tennessee Highway Patrol conducted saturation patrols at every school zone in the county.

They issued 136 citations and gave 107 verbal warnings.

Sheriff's Office authorities say the goal is to make drivers aware of the law -- and to keep people from getting hurt.

Drivers may think they have lots to do behind the wheel, but they really only have one task: To drive carefully. Doing other things while driving amounts to distracted driving.

"In school zones, you have an increased presence with children, parents, teachers, staff and just people generally trying to go to work, which causes congestion in school zones," said Sgt. Tim Belcher.

Under the law, drivers under 18 cannot use a cell phone in a school zone. Older drivers must use a hands-free device.

Belcher said if the public cooperates, officers will write fewer traffic tickets and pull fewer people over.

"What I'm hoping is that the public realizes that we're out there and that we need their voluntary compliance," he said.

All those other things you think you need to do while driving can wait.

"If people would just drive their car and make their phone calls later," he said. "You know, no phone call is worth what can happen if you crash, kill someone. It's just not worth it. You've got to put that cellphone down."