In this subchapter:
(1) "Essential need" means a need of a person to operate a motor vehicle:
(A) in the performance of an occupation or trade or for transportation to and from the place at which the person practices the person's occupation or trade;
(B) in the pursuit of an occupation or trade;
(C) for transportation to and from an educational facility in which the person is enrolled; or
(D) in the performance of essential household duties.
(2) "Ignition interlock device" means a device that uses a deep-lung breath analysis mechanism to make impractical the operation of a motor vehicle if ethyl alcohol is detected in the breath of the operator of the vehicle.
(3) "Offense relating to the operating of a motor vehicle while intoxicated" has the meaning assigned by Section 49.09, Penal Code.