With the North American International Auto Show in Detroit kicking off the auto-show circuit last week, manufacturers are unveiling their future models. If you're inspired and in the market for a new car, FuelEconomy.gov can help you pick the most fuel-efficient vehicle for your needs. Although most people don't bring their computer with them to the dealership, you're in luck if you have a smartphone or other mobile internet device. FuelEconomy.gov has a mobile version of its popular Find and Compare Cars tool that allows you to search anytime, anywhere.

The mobile tool works just like the one on the FuelEconomy.gov website. You don't even need to download an app! Once you go to the mobile site, select a vehicle's model year and make (brand). If there are options for the transmission and engine, click on the preferred option. The screen will then pop up with the specifications for that vehicle. If you would like to compare the vehicle to others, just click on the "compare side-by-side" button to find another vehicle.

Just like its big brother, the mobile tool focuses on fuel economy but provides much more. It illustrates your carbon footprint and petroleum use, so that you can estimate the environmental impact of your potential purchase. It displays an annual fuel cost, allowing you to figure out the real cost of that sports car. Because the database reaches all the way back to 1984, you can even compare used and new cars. If you're interested in an alternative fuel vehicle, the tool also allows you to look at flexible fuel vehicles (FFV) that run on E85 (85% ethanol, 15% gasoline). You can analyze the differences between an FFV's fuel economy, emissions, and fuel cost depending on whether you run it on E85 or gasoline. The mobile Alternative Fueling Station Locator can help you locate fueling stations and/or charging stations on the road.

Whether you're trying to make a wise purchasing decision or just prove to a friend that your car really does get 30 miles per gallon, the Find and Compare Cars mobile tool provides the information you need. In fact, it's so convenient that the White House blog named it one of the "Top 10 Must-Have Government Apps," along with the mobile Alternative Fueling Station Locator. So next time you're thinking about buying a car, be sure to check out the FuelEconomy.gov mobile site first.

Shannon Brescher Shea is the communications manager for Clean Cities in the Vehicle Technologies Program of EERE.