Yellowstone National Park

Drive a Nissan Leaf to see Teddy Roosevelt's "best idea," and save a geyser in the process?

That's probably an exaggeration, but there is some version of that thought process behind the move by some US National Parks to install plug-in vehicle charging stations, says the Huffington Post.

Wyoming's Yellowstone National Park, Utah's Zion National Park and Tennessee's Great Smoky Mountain National Park are among those adding charging stations in a logical move to encourage fuel-free driving through the parks.

In fact, Zion goes one step further by using solar panels to power the charging infrastructure for employee's electric-drive vehicles. Black Bear Solar Institute has provided 24 stations along the Tennessee routes leading to Great Smoky Mountain, which is visited by as many as 10 million people annually.

In all, there were about 14,000 electric-vehicle charging vehicles across the US as of October 31, according to the US Department of Energy.