Huge link here
Two of the roads mentioned, I have bike toured on, and quite enjoyed.
Highway One/Big Sur California
Oh give me a break... My wife and two other friends and I toured this road... it was beautiful. Only the large RVs made it a bit "iffy" in places where there was no shoulder and the road was narrow.Alfred Hitchcock could not have conjured a scarier highway—122 miles of vertigo between Monterey and Morro Bay. Two lanes for nearly its entire length, the road meanders along cliff tops poised high above the Pacific, including 33 bridges and countless drop offs into liquid oblivion. Anyone faintly squeamish should not attempt to drive this route.
Big secret... go slow. Worked fine for cyclists.
The other road...
State Highway 170 Texas
Picturesque is right... the roller coaster aspect simply meant getting speed up enough to go down the dips and try to sprint the humps.This rollercoaster desert road along the Rio Grande is straight out of No Country for Old Men (which was filmed nearby). A dipsy-do roadway, stray animals and floods are just a few of the hazards along the 99 miles of the river road between Lajitas and Candelaria. Much of the highway runs through picturesque Big Bend Ranch State Park.
What makes roads "dangerous" and "scary." Uh, could it be the vehicle operator?