Did You Hear Something Hissing?

Rosemary Marks has a shrewd observation about those tire inflation machines at gas stations:

Then it struck me that it isn't in the interests of gas stations to maintain these machines to do an accurate job. They are interested in selling the gas for profit. Tyre pressure has a huge effect on the fuel efficiency of the vehicle. The worse the fuel economy the more gas you need.

That's the truth. I spent 12 bucks on a gauge recently myself, and the damn thing doesn't work. It said 18lbs, 18lbs, 18lbs, 65lbs.

Great.