Sacramento County (Calif.) General Services Fleet Division is beginning its switch to hybrid models with the replacement of light-duty cars with Toyota Prius models.

The County’s policy requires that a hybrid car replace a gasoline-fueled car when it is no longer economical to own due to wear and costly maintenance. While hybrid cars cost more than a standard gasoline car, the fuel savings over the life of the car offsets its higher purchase price, according to the County.

The Toyota Prius, rated at 50 miles per gallon combined city and highway, is replacing the older gasoline cars that are rated between 20 to 25 miles per gallon combined. The County expects to save $10,000 in fuel savings per vehicle over 120,000 miles.

Currently, the County’s light fleet consists of 2,300 cars and trucks with 350 hybrid cars. Hybrids were chosen over plug-in vehicles because plug-in vehicles are more costly to buy, the CO2 emissions are only slightly lower, and in 2012, according to Department of Energy data, 68% of U.S. electricity is still produced through fossil fuel consumption. Additionally in the fleet are approximately 30 propane vehicles and 100 liquid natural gas refuse trucks in the county’s heavy fleet.