Leaving your car idling while dashing into Blockbuster to return some DVDs or waiting to pick up children from school has long been illegal in 15 states, but only now, according to one of our favorite green blogs, Treehugger, is the law being actively enforced. The law was designed to reduce emissions and oil pollutions, but cities like Denver are enforcing the law to reduce car thefts. Tickets can be up to $475. Watch out for signs at intersections warning about the enforced law if you live in one of the 15 states. Idling produces carbon dioxide, while turning on the car uses a burst of gas. While we may be guilty of not turning off our car in places like bank drive-thrus, we’ll certainly be remembering to while waiting at curb sides or even in bumper-to-bumper traffic. It doesn’t matter why law enforcement is issuing tickets for idling — we’re just happy that it’s drawing more attention to the danger to the environment. We’re sure the EPA is thrilled, too.