When we drive, the engines of our cars, trucks, and other vehicles produce pollutants that contribute, in various ways, to degrading the environment. Recently, a festival of cleaner-running, more Earth-friendly vehicles passed through our area, and I got to test drive a few.

Many of these "green-clean" vehicles are gas-electric hybrids, which combine an electric motor with an internal combustion engine to maximize fuel economy. These hybrids use an electric-drive system with various fuels such as gasoline, ethanol, and propane. Honda has a new gas-electric sedan, the Civic, their second-generation hybrid car. Toyota's gas-electric vehicle, the Prius, can average more than 50 miles per gallon, depending on the length of your trip.

Other cleaner-running vehicles are purely electric. DaimlerChrysler's GEM, for Global Electric MotorCar, is a neighborhood electric vehicle that's already for sale here in the U.S. These have a maximum speed of 25 mph, are certified to operate on roads with speed limits of 35 mph or less, and have been approved for use in more than 30 states.