Take it from the Union of Concerned Scientists: Idling wastes money and fuel, contributes to air pollution, and generates carbon dioxide emissions that cause global warming.
Many states have laws limiting the amount of time vehicles can idle: Visit the Web at www.atri-online.org/research/idling/ATRI_Idling_Compendium.pdf.
Unfortunately, many people believe that idling is necessary or even beneficial - a false perception from the 1970s and 1980s, when engines needed time to warm up (especially in colder temperatures).
Fuel-injection vehicles, which have been the norm since the mid-1980s, can be restarted frequently without engine damage and need no more than 30 seconds to warm up, even on winter days.
Even Click and Clack, the NPR "Car Talk" hosts, say 20 seconds is plenty as long as you drivers don't accelerate to 60 mph immediately.
In fact, idling longer actually damages an engine in the long term. Because an idling engine is not operating at its peak temperature, the fuel does not completely combust, leaving residues in the engine that can contaminate engine oil and make spark plugs dirty. Excessive idling also allows water to condense in the vehicle's exhaust, contributing to corrosion of the exhaust system.
Remember, when first starting your car, idle for no more than 30 seconds. Unless you are sitting in traffic, turn your engine off if you must wait in your car for more than 30 seconds. You can still operate the radio, windows and sometimes even heat without the engine running. So, do yourself and all of us a favor - don't idle.