Pima County's ban on texting while driving takes effect on Thursday.
The ordinance bans the use of handheld electronic devices while driving a car on a street or highway, unless the device is on hands-free mode.
Pima County officials passed the ban in May. The city of Tucson already has a similar ban on texting while driving.
Officials say county sheriff's deputies will give drivers in violation of the ban a written warning instead of a citation during a 60-day grace period. They'll also hand out an educational pamphlet on the matter.