Based on the same system in the Ford Escape Hybrid and Mercury Mariner Hybrid, the latest version is smaller, lighter, more powerful and less expensive to produce. While it still employs nickel-metal hydride batteries, the number of cells has been reduced but the power output remains the same. The battery pack is now 30 percent smaller in volume than the Escape Hybrid's pack and weighs 23 percent less, and this one doesn't need its own AC system to stay cool. The main numbers that everyone wants to know is MPG. Ford expects its new hybrid sedans to achieve 38 mpg in the city, which is 5 mpg better than its most obvious competitor, the Toyota Camry Hybrid. Click here to read Sam's explanation of what Ford did to improve its hybrid powertrain so much.