"The exhaust that comes out of our vehicles is a significant pollutant," and creates just as much pollution as industrial sources, Herbert said.
Amanda Smith, director of the Utah Department of Environmental Quality, said vehicles cause about 40 percent of all air pollution in Utah. "Obviously, that's not all from idling. But reducing idle time is one specific action that is easy to do, and something everyone can do without much impact on their lives," she said.
Herbert noted that the state fleet has 7,300 vehicles that drive 78 million miles a year. The state figures it can save 60,000 gallons of fuel a year through the executive order.
"We get zero miles per gallon when we have our automobiles in idle mode," Herbert said. "Simply put, I think this is a common-sense thing."
He challenged other local governments, industries and citizens "to join with us and be idle-free."
To help enforcement of the order and to measure its success, Alan Matheson, senior environmental adviser to Herbert, said the state will be using "telemetrics" to watch how long some vehicles idle, how far they are driven and their fuel consumption.
Herbert's order includes some exceptions for such things as emergency and highway vehicles that may need to idle to operate warning lights, and for vehicles stopped at traffic lights.
State officials passed out several statistics at Herbert's news conference to help persuade residents to follow the state's example, including:
• 10 seconds of idling can use more fuel than turning off the engine and restarting it.
• Idling uses about a half gallon of fuel per hour.
• It is a myth that an engine should be warmed up before driving. The best way to do that is to drive the vehicle.
Herbert also suggested that instead of idling in a long line for a drive-through restaurant or stopping and starting the engine several times "walk inside and order your food there. It will probably have a shorter line and a shorter wait. So, it's going to take a little bit of an attitude change."
The new executive order is part of the UCAIR Utah Clean Air Partnership campaign that Herbert announced in January to seek ways to help businesses and governments reduce air pollution.