This provision is a "subjective immission" control. It sets a time limit on engine activity. It can also place a curfew on any engine activity. e. In Salt Lake City, UT (Section 4.5.10(xi)) it is considered a "noise disturbance" if the operation lasts more than 15 minutes. Dallas, TX (Section 30–3.1) applies the code to vehicles over 14,000 GVWR; they must be more than 300 feet from a residential zone and there is a 10-minute maximum. They also provide a list of idling vehicles that are exempt from prosecution such as buses or active concrete trucks. Hammond, IN (Section 6.2.10) limits operation to 3 minutes in an hour for vehicles over 14,000 GVWR in either public or private property. It exempts buses and taxis. Massachusetts allows idling no more than 5 minutes.