Dear Tom and Ray:

I've been a school psychologist since 1978, and my assignment has changed somewhat during that time, so it has given me some experiences in several different school buildings. In my current assignment, half an hour before the end of the school day, parents begin parking in a row outside the front door of the school buildings and sit in their cars, with the engines running, until dismissal. I won't embarrass people in this district by reporting the name, but the ZIP code is 50548. I laughed at their poor judgment and wasted gas. If Wiki-answers is right about an average idling car using 0.8 gallons per hour, they are spending $256.96 over the course of 180 school days, at current gas prices.

Then I came home and told my husband about it. He's retired and goes out for coffee three mornings a week. He told me that he drives to the coffee shop over an hour before it opens so he can sit in his favorite parking spot and listen to his favorite CDs on his truck's CD player. Those parents running their cars outside the school buildings look like wise decision-makers by comparison. Does idling a Toyota Tacoma for over an hour at a time hurt the engine?

-- Ann

RAY: I think the Wiki-answers estimate is high, Ann. I'd guess an idling car uses closer to a quarter of a gallon an hour. Maybe a third.

TOM: But that's still throwing away a dollar an hour just to sit there. Not to mention the five or 10 pounds of carbon dioxide you're adding to the environment during that time.

RAY: Unfortunately, we can't help you by claiming that it's bad for the car -- the car really doesn't care. In fact, as long as the cooling system is functioning properly, idling is pretty easy on the car; the engine's not working hard, and the rest of the car is just sitting there.

TOM: So it's really an environmental and economic issue. If your husband is not motivated by either of those -- or those issues are overridden for him by the pleasure he gets from his car stereo and alone time -- you may be out of luck.

RAY: In terms of the school, though, you might want to suggest a "no idling" policy. Lots of states and municipalities have implemented such policies, and a school seems like a particularly good place to do it.

TOM: By sitting there idling for half an hour, not only are the parents contributing to global warming -- a problem their kids will have to live with -- but they're adding pollution to the immediate school environment, where, presumably, kids are playing and learning.

RAY: Or, playing and not learning, in the case of my kids.

TOM: So you might want to start a movement at your school, and see if they'll set a policy and put up some signs along the curb requiring parents to shut off their engines while they wait.

RAY: And let your husband know that you've heard there's a new invention that might interest him. It's called "indoors." And he might want to avail himself of it.

TOM: Although from his point of view, the great indoors has two serious disadvantages: It probably doesn't have as good a sound system as his truck. And, even worse, when you're indoors, you sometimes have to interact with other human beings. I'm guessing that's a deal-breaker for him, Ann.