There are so many wonderful driving tours it's impossible to offer anything like a comprehensive list, but here are a few favorites.
In New England, the dramatic Kancamagus Highway (N.H. 112) cuts through New Hampshire's White Mountains between Lincoln and Conway. Nearby is the privately owned Mount Washington Auto Road, to the top of one of the tallest peaks in the east. The loop road in Maine's Acadia National Park is another beauty.
In the Southeast, you can't beat Virginia's Skyline Drive and the Blue Ridge Parkway, which continues south to North Carolina's Great Smoky Mountains near Asheville.
You'll traverse a wild and undeveloped portion of Monongahela National Forest on the Highland Scenic Highway in West Virginia, a drive that's especially beautiful during fall foliage season.
The Historic Coastal Highway stretches along the eastern coast of Florida, offering up prime ocean views and lots of wildlife.
In the Gulf South, the Natchez Trace Parkway winds through forested beauty in the states of Mississippi, Tennessee, and Alabama on the way from Natchez to Nashville. Another good option in this region is the stunning beauty (including trees, rock formations, and waterfalls) along the Red River Gorge Highway in Kentucky. For picture-perfect views of marshlands and wildlife, look no further than the Creole Nature Trail in Louisiana.
In the Great Plains, a driving tour of Glacier Country in Montana puts you on Going-to-the-Sun Road through Glacier National Park, one of the great summertime drives in the country. Over the border in Wyoming, the Beartooth Scenic Byway (U.S. 212) from the northern part of Yellowstone National Park east to Red Lodge climbs over 10,947-foot Beartooth Pass, from where you can see mile upon mile of Wyoming and Montana mountains. Custer State Park in the South Dakota Badlands offers not one, but three scenic auto routes, though if you have time for only one, make it Iron Mountain Road.
In Colorado, a driving tour of the Western Slope follows the Million Dollar Highway (U.S. 550) across 11,008-foot Red Mountain Pass, an unforgettable drive. The San Juan Skyway, a 236-mile circuit that crosses five mountain passes, takes in the magnificent scenery of the San Juan Mountains, including some wonderful Old West towns. And visitors to Rocky Mountain National Park should not pass up a drive on the exceptionally scenic Trail Ridge Road, especially in spring when the wildflowers are in bloom and wildlife is out in force.
In the Southwest, the Kaibab Plateau -- North Rim Parkway winds itself through the trees of Kaibab National Forest before landing at the scenic northern edge of the Grand Canyon. In the Arizona desert, the drive from Phoenix through Prescott and Sedona includes huge red rocks and the cool oasis of Oak Creek Canyon. The desert's most spectacular scenery is in Monument Valley on the Arizona-Utah border in Navajo and Hopi country and the nearby Canyonlands.
Out in California and the Pacific Northwest, driving doesn't get any more dramatic than it is along the California and Oregon coasts.
Up in Alaska, one of the world's great drives begins in Anchorage and leads roughly 50 miles south on the Seward Highway to Portage Glacier; chipped from the rocky Chugach Mountains, the Turnagain Arm provides a platform for viewing an untouched landscape full of wildlife.
Out in Hawaii, the drive from Honolulu to Oahu's Windward coast on Hwy. 61 offers an unparalleled view down from the near-vertical Pali cliff. The narrow, winding Hana Road on Maui will reward your driving skills with wonderful seascapes.
For a comprehensive list of the major scenic byways and roads in the U.S., check out the U.S. Department of Transportation's America's Byways website at www.byways.org; while you're online, be sure to request their free America's Byways map.