3500 ft drop over 13 miles. I-80 down from the mountains into Salt Lake City. Curvy canyon road, but built to interstate specs so the curves were wide and not too sharp. 2 AM so traffic was almost zero. Speed got slightly above the limit, but no more than you'll find every day on most highways.
https://maps.google.com/maps?saddr=I...p=0&sz=12&z=12
Daily I have a 1-mile coast if lights and traffic cooperate.
Here's another one I've done, 2000 ft drop over 12 miles. Cabbage Hill in Oregon.
https://maps.google.com/maps?saddr=I...p=0&sz=13&z=12