That's what those run-away truck ramps are for on down-hill sections of mountain road in the Rocky Mountain states.
But it's more fun letting her rip like Earl did.

Wolf Creek Pass is at more than 10,800 feet where it crosses the Great Divide. They have made hwy 160 into a 4-lane, taking the fun out of the old 2-lane road, but grades are only moderate so it's an easy road in summer weather.