Tourism in Denali National Park, home to 20,320-foot Mount McKinley, could get a lot greener before we know it.

If you've been to Denali you know that the park forbids personal cars for the 92-mile length of the park road. Instead, visitors catch a diesel bus near the park entrance. The road is the only way to get into and out of the park.

Park officials are now testing out a hybrid tour bus to eventually replace the fleet of 110 diesel buses that take thousands each year to view North America's highest mountain and the wildlife that surrounds it.

Officials tell the Associated Press that these hybrids reduce the amount carbon dioxide emissions by 40 percent, nitrogen oxide emissions by another 20 percent and particulate emissions by 30 percent.

That translates into a much more environmentally friendly vehicle for one of the country's most beautiful...environments.

Officials are also touting the gas efficiency of the hybrids, since diesel fuel in the area is topping out at around $5 a gallon. The hybrid bus requires around 70 percent less fuel as the park's current diesel buses.

The hybrid system combines a diesel engine with an 80-kilowatt powertrain that incorporates a transmission, batteries and an electric motor, the AP reports.

Right now the park is looking to slowly phase out its diesel fleet, and officials tell the AP it could replace anywhere from two to 12 buses each year with the hybrid models.

But this will come with a significant price tag: Each hybrid bus costs $200,000 -- twice as much as the buses currently in use.

Filed under: North America, United States, Transportation, Ecotourism