The report looked at whether federal agencies use original or remanufactured parts to fix vehicles and found that agencies have different policies on whether to use them.

Remanufactured parts are generally cheaper. The U.S. Postal Service said it “relies heavily on the remanufacturing industry to sustain our vehicle.”

The U.S Postal Service’s fleet of nearly 210,000 vehicles are on average 16.2 years old, while Homeland Security’s 48,917 vehicles are four years old on average.

The General Services Administration’s fleet of 200,000 vehicles are 3.5 years old on average and need far less maintenance than other fleets.

Some agencies like the FBI, U.S. Postal Service and Customs and Border Patrol, use in-house garages for some maintenance and repair work.