RICHMOND, VA --- Online used-car retailer CarMax Inc. said that searches for hybrids on were up 43 percent from March to July. In response to the growing demand for information about fuel efficiency, CarMax is offering the following tips for shopping for a used hybrid or a more fuel-efficient vehicle:

* Do your research on hybrid vehicles. Hybrids combine a gasoline engine with an electric motor powered by batteries. The electric motor helps increase the engine's fuel efficiency.

* Learn what type of hybrid is best for you -- a full or mild hybrid? A full hybrid can at times be powered by an electric motor independent of a gas engine. The electric motor gives it the ability to obtain more miles to the gallon than a non-hybrid. A mild hybrid uses its electric motor only to assist the gasoline engine when more power is required.

* Investigate whether your state offers tax credits or HOV access for hybrid owners. Some states still offer some benefits, although the laws are changing.   

* Research non-hybrid, fuel-efficient cars that also offer better-than-average mileage. Some non-hybrids like the Honda Fit and Toyota Corolla can get up to 35 mpg highway.

* Hybrid and non-hybrid versions of the same car differ in price. The hybrid version can cost up to $5,000 more, so be prepared to pay more upfront to save money in the long run. recently launched an "MPG" search feature to aid shoppers when researching vehicles by their estimated miles per gallon. The website can be used to research information on vehicles of various makes and models. For more information, visit