Note the Texas exemptions...
Only applies to the following:
State Codes (only currently applicable to the following counties: Bastrop, Caldwell, Hays, Travis, Williamson and the following cities: Austin, Bastrop, Elgin, Lockhart, Round Rock, San Marcos)
The provisions of §114.512 of this title (relating to Control Requirements for Motor Vehicle Idling) do not apply to:
(1) a motor vehicle that has a gross vehicle weight rating of 14,000 pounds or less;
(2) a motor vehicle forced to remain motionless because of traffic conditions over which the operator has no control;
(3) a motor vehicle being used by the United States military, national guard, or reserve forces, or as an emergency or law enforcement motor vehicle;
(4) the primary propulsion engine of a motor vehicle providing a power source necessary for mechanical operation, not including propulsion, and/or passenger compartment heating, or air conditioning;
(5) the primary propulsion engine of a motor vehicle being operated for maintenance or diagnostic purposes; (6) the primary propulsion engine of a motor vehicle being operated solely to defrost a windshield;
(7) the primary propulsion engine of a motor vehicle that is being used to supply heat or air conditioning necessary for passenger comfort/safety in those vehicles intended for commercial passenger transportation or school buses in which case idling up to a maximum of 30 minutes is allowed;
(8) the primary propulsion engine of a motor vehicle used for passenger transit operations in which case idling up to a maximum of 30 minutes is allowed;
(9) the primary propulsion engine of a motor vehicle being used as airport ground support equipment; or
(10) the owner of a motor vehicle rented or leased to a person who operates the vehicle and is not employed by the owner.