Garmin announced its latest nav-system add-on, called ecoRoute, at the 2009 International Consumer Electronics Show in Las Vegas this week. The application, which will ready for download in February, allows drivers to choose “less fuel” as a route calculation, in addition to “faster time” and “shorter distance.”

Besides just calculating the gas-sipping-est way from here to there, ecoRoute compiles a Fuel Report and Mileage Report to keep drivers informed of their gas usage over time and per trip. It even has little fuel-saving messages that pop up as text on the screen.

EcoRoute is compatible with the 205 and 705 series of the Garmin Nuvi satellite nav systems. Honda and Ford have recently announced similar built-in systems for their upcoming models, according to Edmunds.com’s Green Car Advisor.