(a) Commercial motor vehicle.--Except as provided under subsection (c), a driver may not use a handheld mobile telephone while driving a commercial motor vehicle or motor carrier vehicle.

(b) Employer.--Except as provided under subsection (c), an employer may not permit or require a driver of the employer to use a handheld mobile telephone while driving a commercial motor vehicle or a motor carrier vehicle.

(c) Emergency use exception.--Using a handheld mobile telephone shall be permissible by a driver of a commercial motor vehicle or motor carrier vehicle if necessary to communicate with a law enforcement official or other emergency service.

(e) Definitions.--As used in this section, the following words and phrases shall have the meanings given to them in this subsection:

“Driving.” Operating a commercial motor vehicle or motor carrier vehicle on a highway, with the motor running, including while the commercial motor vehicle or motor carrier vehicle is temporarily stationary because of traffic, a traffic control device or other momentary delay. The term does not include operating a commercial motor vehicle or motor carrier vehicle with or without the motor running if the driver moved the vehicle to the side of or off of a highway and halted in a location where the vehicle can safely remain stationary.

“Mobile telephone.” A mobile communication device which uses a commercial mobile radio service, as defined in 47 CFR § 20.3 (relating to definitions). The term does not include two-way or Citizens Band Radio services.

“Use a handheld mobile telephone.” As follows: