WAILUKU » Maui County is participating in the testing of a converted plug-in hybrid electrical vehicle that doubles mileage and reduces greenhouse gases.

“;This is the direction we must go in,”; Maui Mayor Charmaine Tavares said before taking a test drive yesterday. “;This thing is just wonderful. It's a great, great thing.”;

The testing is sponsored by the Idaho National Laboratory and the U.S. Department of Energy's Advanced Vehicle Testing Activity program.

The conversion included the installation of a 5-kilowatt-hour, lithium-ion battery pack and a 110-volt charging port in the rear of a county-owned 2007 Toyota Prius. The new battery allows the hybrid car to run longer on electricity and to plug into the electric grid.

The standard Prius gets about 40 to 45 miles a gallon on a gasoline engine and a fuel-charged, nickel-metal-hydride battery system that switches to gas use when traveling above 35 mph.

The conversion enables drivers to get 80 to 95 miles a gallon, officials said.

The conversion was done at the automotive program building at Maui High School, where students were able to view the installation. The vehicle is expected to use the facility later to install improved software.

“;It's a great opportunity. It's going to take the program to the next level,”; said school Principal Randy Yamanuha.

Others participating in the conversion program include Maui Electric, Hawaiian Electric, the University of Hawaii, the state and the Air Force.

The Idaho National Laboratory is tracking more than 100 converted vehicles nationwide and in Canada to determine driving habits.