WASHINGTON — Want to know the exact savings that your car can score from various energy-saving strategies?

Take the Drive $marter Challenge that the Alliance to Save Energy is launching today.

Enter your car's model and year at www.drivesmarterchallenge.org, and the site will tell you the total you can save from the six easiest energy-saving moves. A lot depends on the vehicle.

For example, the driver of a 2008 Volkswagen Passat Wagon — one of the most fuel-efficient midsize station wagons — can save $444 a year, assuming an average gas price of $3.79 a gallon

On the other hand, a driver with a 2008 Mercedes-Benz E63 AMG wagon — one of the least fuel-efficient midsize wagons — can save $761 a year.

In rank order, and with the maximum savings in parentheses, these are the simplest steps for the average car:

• Speed costs. Gas mileage decreases rapidly above 60 mph. Stay under that limit and ...

• Avoid jackrabbit starts and rapid braking. (Together they'll save up to $255 a year.)

• Reduce your miles traveled by 5 percent ($100 a year)

• Keep tires properly inflated ($65 a year.)

• Ditch the junk in the trunk ($40 a year for each 100 pounds.)

• Select the right oil ($40 per year)