The Montana Department of Transportation says the state has surpassed goals to reach an average of 30 miles per gallon in its fleet of vehicles by 2010, according to the Associated Press.

The agency has already surpassed that goal at 31 miles per gallon, partly by adding 98 hybrid vehicles to its fleet.

The department plans to buy another 27 new hybrids this spring, including some SUVs. The Ford Escape SUV is among the 98 hybrids the department has already added, along with the Toyota Prius and Honda Civic.

Factoring the 27 new hybrids into the mix, the department will increase its fleetwide average of 31.6 miles per gallon to 34.2 miles per gallon, said department director Jim Lynch. That mileage will continue to increase when some of the older cars still in the fleet are replaced.

In addition to the benefit of saving the state money on fuel costs, hybrids' resale value is often higher, although the vehicles do cost more.