These Parking Meters Know If You're Driving a Gas-Guzzler - Businessweek

In Chicago, the parking meters could simply query nearby lamp posts for car details

"In Madrid, parking meters are joining the fight against air pollution. Starting July 1, newly installed “smart” meters in the Spanish capital will charge higher parking fees to vehicles that guzzle fuel or emit clouds of exhaust fumes.

After pulling into a parking space, drivers will be prompted to enter their license plate number on a keypad on the meter, which is networked into Spain’s vehicle-registration database. The meter then will set a parking rate based on the car’s age and model. Hybrids and other newer, fuel-efficient cars will get a discount of up to 20 percent, while older vehicles and diesel-powered models will pay a surcharge of as much as 20 percent, according to local press reports."

These Parking Meters Know If You're Driving a Gas-Guzzler - Businessweek