No-idling Restrictions for Heavy-duty Vehicles To Improve Air Quality

Published 12:00 am Thursday, March 3, 2011

A new North Carolina rule requires operators of heavy-duty vehicles to reduce unnecessary idling. The rule is part of the state’s efforts to reduce air pollution, protect public health and meet more stringent federal air quality standards.

The idle-reduction rule applies to on-road gasoline and diesel-powered vehicles with loaded weights greater than 10,000 pounds. Under the rule, operators should not idle their vehicles more than five consecutive minutes in any 60-minute period except for certain cases dealing with safety, health or economic concerns.

Complying with the idle rule will save operators both fuel and money.  A heavy-duty vehicle typically burns about one gallon of fuel per hour while idling. Rising fuel prices alone offer a compelling reason to reduce idling when possible.

Idling vehicles are significant sources of air pollution. The N.C. Division of Air Quality (NCDAQ) estimates the rule will reduce nitrogen oxide (NOx) emissions, the primary cause of ozone pollution, by up to 1,300 tons per year statewide. In comparison, a medium-sized coal-fired power plant typically emits about 500 tons of NOx a year.

The rule could reduce emissions of carbon dioxide, the most common greenhouse gas, by as much as 100,000 tons per year. Exhaust from idling vehicles also contains fine particles and toxic air pollutants that can pose health risks for truckers and other people at highway rest areas, truck stops and other places where idling vehicles congregate.

The rule makes allowances for cases when idling may be necessary.  For example, operators of emergency vehicles such as fire trucks can idle while responding to emergencies or during training exercises. Heavy-duty vehicles can idle when it’s necessary to operate equipment that depends on their engines, such as hoists and refrigerators.

For a copy of the the state law and list of exemptions, visit: