Chip from Somerville, NJ was complaining about his neighbors running their car for a long time in the morning. He should just tell them that they’re breaking the law. In NJ, it is illegal to idle a vehicle for more than 3 minutes. See http://www.state.nj.us/dep/aqm/Sub15.pdf, specifically, section 7:27-15.8 (note that a similar law applies to diesel-fueled vehicles):
§ 7:27-15.8 Idle standard
(a) No person shall cause, suffer, allow, or permit the engine of a gasoline-fueled motor vehicle to idle for more than three consecutive minutes if the vehicle is not in motion.
(b) The provisions of (a) above shall not apply to:
- Autobuses while actively discharging or picking up passengers. This exemption is limited to 15 consecutive minutes in a 60-minute period;
- Any motor vehicle idling in traffic, or a motor vehicle other than a school bus idling in a queue of motor vehicles, that are intermittently motionless and moving because the progress of the motor vehicles in the traffic or the queue has been stopped or slowed by the congestion of traffic on the roadway or by other conditions over which the driver of the idling motor vehicle has no control;
- Motor vehicles whose primary and/or secondary power source is utilized in whole or in part for necessary and definitively prescribed mechanical operation other than propulsion. This use includes, but is not limited to, operating lift gate pumps and controlling cargo temperature. This exemption does not apply to passenger compartment heating or passenger compartment air conditioning;
- Motor vehicles being or waiting to be examined by State or Federal motor vehicle inspectors;
- Vehicles that are actively performing emergency services. Examples include fire vehicles, police vehicles, public utility vehicles, military tactical vehicles and snow removal vehicles, during the time that such vehicles are actively performing emergency services;
- Motor vehicles while being repaired or serviced, provided that operation of the engine is essential to the proper repair or service; or
- Motor vehicles manufactured with a sleeper berth while being used, in a non-residentially zoned area, by the vehicle‘s operator for sleeping or resting, unless the vehicle is equipped with a functional auxiliary power system designed in whole or in part to maintain cabin or sleeper berth comfort or to mitigate cold weather start-up difficulties.