WASHINGTON- The U.S. Postal Service will replace 6,500 aging units in its delivery fleet with 1,000 E-85, 900 gasoline/electric hybrid, and 4,600 four-cylinder vehicles fully funded by the General Services Administration (GSA).

The 1,900 vehicles from GSA will bring the total number of alt-fuel vehicles in the Postal Service fleet to more than 43,000.

"With our fleet traveling more than 1.2 billion miles a year, the Postal Service consistently looks for ways to reduce the environmental footprint that results from visiting every home and business in America six days a week," said Sam Pulcrano, vice president, Sustainability.

The Postal Service has increased alternative-fuel use by 41 percent since 2006, and plans to reduce petroleum use by 20 percent over the next five years. Replacing aging vehicles with more fuel-efficient and alternative fuel-capable vehicles is key to reaching that goal.

Other efforts the Postal Service has taken to reduce the environmental impact of its fleet include:

• Three-wheel (T3) electric vehicles on a trial basis in Florida, California, and Arizona. The T3 is powered by two rechargeable batteries, has zero gas emissions and costs 4 cents a mile to operate.

• Two fourth generation fuel-cell Chevrolet Equinox hydrogen fuel-cell vehicles tested to deliver mail in Irvine, Calif., and in Washington.

• 35 propane-fueled delivery vehicles in Florida.

• 300 vehicles nationwide powered by biodiesel fuel.