Idle Reduction Requirement
Idling of any unattended vehicle is prohibited in Utah. Violators are subject to a penalty of up to $750 and/or up to 90 days imprisonment. Drivers on state roads are also encouraged to avoid excessive idling, which, as a general rule, is defined as more than 10 to 15 seconds for passenger vehicles. Specifically, drivers are encouraged to turn off engines when loading or unloading, delivering, and picking up or dropping off passengers. Drivers of gasoline powered passenger vehicles are encouraged to limit engine warm-up time to 30 seconds and drivers of diesel powered passenger vehicles, buses, and trucks are encouraged to limit engine warm-up to the time the vehicle manufacturer recommends, which is generally less than five minutes. Businesses, schools, airport authorities, and governmental entities are encouraged to post signs to discourage customer idling.
(Reference Utah Code 41-6a-202, 41-6a-1401, 76-3-204, and 76-3-301)