Vehicle Idling

Exhaust fumes from gasoline and diesel engines contain harmful pollutants including nitrogen oxides, carbon monoxide, volatile organic compounds, and fine particles that can make it difficult to breathe; cause respiratory infections and chronic bronchitis; and trigger asthma attacks. Unnecessary idling also wastes fuel and releases greenhouse gases contributing to global warming.

The Massachusetts Anti-Idling Law prohibits unnecessary vehicle idling, requiring that the engine be shut down if the vehicle will be stopped for more than five minutes. There are three exceptions: (1) when the vehicle is being repaired and idling is necessary to make the repair; (2) the vehicle is making deliveries and needs to keep its engine running (e.g., to power refrigerators); or (3) the vehicle's accessory equipment needs to be powered (e.g., to defrost the windshield while actively clearing off snow and ice). Leaving your car running to let the heater warm it up or air conditioning cool it down is considered unnecessary idling.

In order to reduce the health and environmental effects of vehicle exhaust, comply with the state's idling reduction regulation and law, and decrease fuel use, please limit idling to five minutes in fleet and personal vehicles.