When used in this article, the following words, terms and phrases shall have the meanings ascribed to them, except where the context clearly indicates a different meaning:
Commercial passenger transportation.
A mode of transportation provided by a bus or motor coach designed to accommodate more than ten (10) passengers, including the operator, for compensation, and that is powered by a primary propulsion engine, and does not include railroads, light rail or taxicabs.
Idle.
The operation of an engine in the operating mode, where the engine is not engaged in gear, where the engine operates at a speed at the revolutions per minute specified by the engine or vehicle manufacturer for when the accelerator is fully released, and there is no load on the engine.
Mechanical operations.
Use of electrical tools or equipment in construction, maintenance, or repair of facilities.
Passenger transit operations.
A regional mode of public transportation that is funded through a portion of sales tax for such region being served.
Primary propulsion engine.
A gasoline- or diesel-fueled internal combustion engine attached to a motor vehicle that provides the power to propel the motor vehicle into motion and maintain motion.
(2007 Code, sec. 12.06.001)
No person shall cause, suffer, allow, or permit the primary propulsion engine of a motor vehicle to idle more than five (5) consecutive minutes when the motor vehicle is not in motion.
(2007 Code, sec. 12.06.003)
The following constitute affirmative defenses to prosecution under this article:
(1) 
The motor vehicle has a gross vehicle weight rating of 14,000 pounds or less;
(2) 
The motor vehicle is/was forced to remain motionless because of traffic conditions over which the operator has no control;
(3) 
The motor vehicle is being used by the United States military, national guard, or reserve forces, or as an emergency or law enforcement vehicle;
(4) 
The primary propulsion engine of the motor vehicle provides a power source necessary for mechanical operation, not including:
(A) 
Propulsion; and
(B) 
Passenger compartment heating and air conditioning;
(5) 
The primary propulsion engine of the motor vehicle is being operated for maintenance or diagnostic purposes;
(6) 
The primary propulsion engine of a motor vehicle is being operated solely to defrost a windshield;
(7) 
The primary propulsion engine of a motor vehicle is being used to supply heat or air conditioning necessary for passenger comfort/safety in those motor vehicles intended for commercial passenger transportation or school buses, in which case idling up to a maximum of thirty (30) minutes is allowed;
(8) 
The primary propulsion engine of a motor vehicle is used for passenger transit operations, in which case idling up to a maximum of thirty (30) minutes is allowed;
(9) 
The primary propulsion engine of a motor vehicle is being used as airport ground support equipment;
(10) 
The primary propulsion engine of a motor vehicle is being used to provide air conditioning or heating necessary for employee health or safety while the employee is using the vehicle to perform an essential job function related to roadway construction or maintenance; or
(11) 
A motor vehicle when idling is necessary to power a heater or air conditioner while a driver is using the vehicle’s sleeper berth for a government-mandated rest period. This subsection expires September 1, 2007.
(2007 Code, sec. 12.06.004)
For any violation of this article, the person seeking to establish an affirmative defense shall have the burden of proving by a preponderance of the evidence that an event that would otherwise be a violation of this article was caused by one of the affirmative defenses allowed in section 22.06.004.
(2007 Code, sec. 12.06.005)
This article is not intended to relieve any person or persons from the responsibility of complying with the Texas Transportation Code, section 545.404 (unattended motor vehicle), or any other state law it may conflict with.
(2007 Code, sec. 12.06.006)