Personally I think there will be many years of Level 4 before level 5 is sufficiently developed. Initially, I believe, Level 4 will be confined to cities. The major cities will have fleets of autonomous cabs, and as technology improves the autonomous vehicle will be rolled out wider and wider.
Having said that, a self driving vehicle, on a road like you quoted, will probably be a lot safer than most drivers. It won't push on just because it is a 4x4 and will intimidate smaller vehicles, it will more easily be able to compute the speed of oncoming vehicles, using its sophisticated LIDAR (judging speed of approaching vehicles is the most difficult task for humans, especially as they get older, and is one of the reasons many older motorists end up in accidents), and the wheel and inertia sensors on autonomous vehicles make excellent choices regarding road surface and grip.