When looking for fuel-saving technology within a model line, Honda?TEC-E system, available on its Civic, is one such example. A version of Honda?ariable valve Timing and Electronic lift Control, VTEC-E creates a swirling effect in the combustion chamber that allows for an extremely lean air-fuel mixture at low revs to increase fuel economy.

And it succeeds: the Civic HX with a VTEC-E equipped 4-cylinder engine achieves 36 mpg city and 44 mpg highway, a respective four mpg city and six mpg highway improvement over a different iteration of Honda?.7-liter engine in the same model.

Be on the lookout for up-and coming technologies that improve efficiency. General Motors and Ford are jointly developing a new 6-speed automatic transmission that will begin appearing in front- and all-wheel drive models in 2006, bringing with it fuel economy improvements of up to four percent. Automakers such as Honda, General Motors, and DaimlerChrysler are also beginning to employ cylinder deactivation technology in their models, which reduces fuel consumption by shutting off a number of cylinders under certain driving conditions. The system effectively turns a V-8, for example, into an inline four when power demands are low, thus burning less fuel.