(a) In this section:
(1) “Hands-free device” means speakerphone capability, a telephone attachment, or another function or other piece of equipment, regardless of whether permanently installed in or on a wireless communication device or in a motor vehicle, that allows use of the wireless communication device without use of either of the operator’s hands, except to activate or deactivate a function of the wireless communication device or hands-free device. The term includes voice-operated technology and a push-to-talk function.
(2) “Wireless communication device” means a device that uses a commercial mobile service, as defined by 47 U.S.C. § 332.
(b) Except as provided by Subsection (c), an operator may not use a wireless communication device while operating a motor vehicle within a school crossing zone, as defined by § 541.302, Transportation Code, unless:
(1) the vehicle is stopped; or
(2) the wireless communication device is used with a hands-free device.

(b-1) Except as provided by Subsection (b-2), a local authority that enforces this section in a school crossing zone in the local authority’s jurisdiction shall post a sign, or approve the posting of a sign by a school or school district, that complies with the standards described by this subsection at each entrance to the school crossing zone. The Texas Department of Transportation shall adopt standards that:
(1) allow for a sign required to be posted under this subsection to be attached to an existing sign at a minimal cost; and
(2) require that a sign required to be posted under this subsection inform an operator that:
(A) the use of a wireless communication device is prohibited in the school crossing zone; and
(B) the operator is subject to a fine if the operator uses a wireless communication device in the school crossing zone.
(b-2) A local authority that by ordinance or rule prohibits the use of a wireless communication device while operating a motor vehicle, including a prohibition that contains an exception for the use of a wireless communication device with a hands-free device, throughout the jurisdiction of the local authority is not required to post a sign as required by Subsection (b-1) and shall:
(1) post signs that are located at each point at which a state highway, U.S. highway, or interstate highway enters the jurisdiction of the local authority and that state:
(A) that an operator is prohibited from using a wireless communication device while operating a motor vehicle in the jurisdiction of the local authority, and whether use of a wireless communication device with a hands-free device is allowed in the jurisdiction of the local authority; and
(B) that the operator is subject to a fine if the operator uses a wireless communication device while operating a motor vehicle in the jurisdiction of the local authority; and
(2) subject to all applicable United States Department of Transportation Federal Highway Administration rules, post a message that complies with Subdivision (1) on any dynamic message sign operated by the local authority located on a state highway, U.S. highway, or interstate highway in the jurisdiction of the local authority.
(b-3) A sign posted under Subsection (b-2)(1) must be readable to an operator traveling at the applicable speed limit.
(b-4) The local authority shall pay the costs associated with the posting of signs under Subsections (b-1) and (b-2), unless the authority enters an agreement providing otherwise.
(c) An operator may not use a wireless communication device while operating a school bus or passenger bus with a minor passenger on the bus unless the bus is stopped.
(d) It is an affirmative defense to prosecution of an offense under this section that:
(1) the wireless communication device was used to make an emergency call to:
(A) an emergency response service, including a rescue, emergency medical, or hazardous material response service;
(B) a hospital;
(C) a fire department;
(D) a health clinic;
(E) a medical doctor’s office;
(F) an individual to administer first aid treatment; or
(G) a police department; or
(2) a sign required by Subsection (b-1) was not posted at the entrance to the school crossing zone at the time of an offense committed in the school crossing zone.
(d-1) The affirmative defense available in Subsection (d)(2) is not available for an offense under Subsection (b) committed in a school crossing zone located in the jurisdiction of a local authority that is in compliance with Subsection (b-2).
(e) This section does not apply to:
(1) an operator of an authorized emergency vehicle using a wireless communication device while acting in an official capacity; or
(2) an operator who is licensed by the Federal Communications Commission while operating a radio frequency device other than a wireless communication device.
(e-1) Subsection (c) does not apply to an operator of a school bus or passenger bus using a wireless communication device:
(1) in the performance of the operator’s duties as a bus driver; and
(2) in a manner similar to using a two-way radio.
(f) Except as provided by Subsection (b-2), this section preempts all local ordinances, rules, or regulations that are inconsistent with specific provisions of this section adopted by a political subdivision of this state relating to the use of a wireless communication device by the operator of a motor vehicle.