We have a 35% grade road near me with switch backs of 45* every 100 feet. It is only about a mile long but the trucks go up and down it at about 10 mph. There have been several dozen car wrecks on it over the past 10 years. They mainly get fubar’d going down hill on the last 100 yards where there is a sudden rise and 30* negative fall away in the middle of a 45* right turn. They slide across the road airborne into the 20 ton granite boulders on the opposite side.