With gas prices soaring and polar ice caps melting, car companies are championing their fuel-efficient models. But the saintly hybrid may not be your best option. Here's a breakdown of the types of cars that use alternative fuels and how to determine which one is right for you. Ian Daly

HYBRID

The Gist: The half-gas, half-electric engine is replenished by kinetic energy from braking.
The Upside: Great for stop-and-go traffic
The Downside: Fuel-economy payoff is generally minor considering the higher price tag.
Buy If: You have a bumper-to-bumper commute or drive in a city
The Ride: Lexus GS 450h ($52,975)

Courtesy of About.com

DIESEL

The Gist: The trucker fuel is more efficient than regular gas, and now it's cleaner.
The Upside: Good for long distances—gas contains more energy per unit than the standard stuff
The Downside: Slower, and requires special impurity-filtering tanks that need changing
Buy If: You have a traffic-free commute or drive on uncrowded highways
The Ride: BMW 335d (approximately $45,000, October release)

Courtesy of Carsandtuning.org

PLUG-IN HYBRID

The Gist: It's similar to the hybrid, but you can also plug it in to charge it.
The Upside: Uses no gas for short commutes
The Downside: Long charge time (overnight)
Buy If: You have short commutes in traffic but also take longer trips
The Ride: Fisker Karma ($80,000, 2010 release)

Courtesy of Autoreviewcity.com

ELECTRIC

The Gist: The only energy source for the fully electric car is its battery.
The Upside: Zero emissions, no trips to the gas station, and fast acceleration
The Downside: Short range and long charge time
Buy If: You never drive more than 200 miles a day
The Ride: Tesla Roadster ($109,000)

Courtesy of Elementale.com

FLEX FUEL

The Gist: Equipped to burn up to 85 percent ethanol (E85), these models take regular gas, too.
The Upside: Better for air quality and easy on your wallet (since E85 is cheaper than regular gas)
The Downside: E85 is still hard to find and gets inferior mileage.
Buy If: You live close to the source of the fuel: cornfields
The Ride: 4.7L Jeep Grand Cherokee ($29,215)

Courtesy of Motor Daily