Campground road at Stanton Creek CG in Bullfrog, UT. If the water was higher/closer it would be a lot better, but it's still very washboard-y:
Someone mentioned the Moki Dugway, which was mildly scary but actually a pretty good surface:
Yes, California roads can be terrible, and full of traffic. The worst I can remember is the road from Highway 89 near Camp Richardson at Lake Tahoe back to the Fallen Leaf Lake campground, and further back to the end where the marina is. That is scary and rough even in a car. I think it was last maintained sometime in the 70's.