As long as the engine's on, soot still spews into the sky. Now Dane County Board member Brett Hulsey is taking a closer look at those emissions that come from idling diesel engines.
"You see that black gunk coming out of there," said Hulsey. "That's soot particulate, that lodges in the lungs, causes heart attacks, asthma attacks."
Under the proposal now referred to a Dane County health health commitee, any diesel engine, large and small, couldn't idle for more than five minutes on unincorpated land in the county.
In Madison, members of the commission on the environment are studying if the idea should be implemented in the city as well.
"Diesel is ten to one hundred times dirtier than a gas engine, which is why we're focusing on diesel," said Hulsey.
"Not only do you have CO2 emissions, but there's the soot particulate, the fine particulate that gets released, and that definitely has health effects associated with it," said Jonathan Standridge, a member of the committe on the environment, which listened to a presentation from Hulsey on Monday.
The biggest effect of any diesel idling proposal could be on long haul truckers. An idling engine helps them sleep in comfort at truck stops for hours, especially on hot or cold nights.
"It's a little unrealistic to ask them to wake up every fifteen minutes and start up the engine, then turn it off and go back to bed for another 45 minutes," said Tom Howells, president of the Wisconsin Motor Carrier Association.
Howells said his group's board is meeting Tuesday to discuss the proposal, and won't have a stance on it until then. He said, however, that diesel drivers do share a common goal with environmentalists. "Clearly it's a win-win with less emissions and with fuel the way it's been, it's less money spent on fuel," he said.
The thought of a tiket for not turning off the truck might not sit well, especially for delivery drivers who leave a truck running for an extra minute.
"It's a complaint based system, we're not going to put the diesel police on the streets," said Hulsey.
Hulsey said the proposal makes several exceptions, including for emergency vehicles and those that delivery food and need refridgeration.
This idea isn't new, either. Similar idling laws are already in place in Minneapolis, Sacramento, and Dallas. At some trucks stops in the Southeast, stations are equipped with devices that pump in air conditioning. The Wisconsin Department of Commerce also began a grant program two years ago allowing diesel truck drivers to pay for equipment that would reduce emissions while trucks idle.