Sure, cars and trucks are convenient, and most of us couldn't live without them, but they have become very expensive to run and harmful to the environment. Gas prices have been hovering around $2 a gallon, and carbon-dioxide emissions from cars pollute the environment and contribute to global warming. As a result, hybrid cars and electric cars have emerged as economical and Earth-friendly alternatives to conventional vehicles.

Hybrid Cars

Hybrid vehicles combine two sources of energy such as a battery-powered electric motor and a conventional internal combustion engine. The driver decides which source of power is appropriate for a given journey. Short jaunts to the grocery store or the post office could use the electric motor, while weekends in the country may require the internal combustion engine. The Honda Insight and the Toyota Prius are popular hybrid cars. In late 2004, Ford introduced the first hybrid SUV, the Escape.

Electric Cars

Electric cars run on rechargeable batteries rather than fuel. They also don't have a transmission, a radiator or hoses. The best thing about them is they cause about 97% less pollution than regular cars. But there are some downsides, too. The battery runs out of juice after driving between 100 and 140 miles, and it takes about eight hours to recharge the battery. Electric cars also are expensive. Their batteries cost $2,000 and wear out in just a few years. And, ironically, electric cars do very little to reduce carbon dioxide emissions because most electricity in the U.S. is generated by burning coal and other fossil fuels.