I thought Google's Street View cars couldn't drive very fast to be able to take those pictures. When not driving at full speed, it's not really a good learning set.
I'd argue that the vast majority of the roads where one drives faster than 50 km/h are very simple. This is especially true for highways; they have to be, because humans are bad at thinking at 120 km/h and even worse at surviving collisions at that speed. There's an overabundance of signs and road marking, and an incredible effort has been put into making it relatively hard for drivers to behave irrationally. Compare that with, say, a multi-lane roundabout in the inner city.
Once you've got enough data to reliably survive that kind of situation, you're 90% of the way there.
I'd argue that the vast majority of the roads where one drives faster than 50 km/h are very simple. This is especially true for highways; they have to be, because humans are bad at thinking at 120 km/h and even worse at surviving collisions at that speed. There's an overabundance of signs and road marking, and an incredible effort has been put into making it relatively hard for drivers to behave irrationally. Compare that with, say, a multi-lane roundabout in the inner city.
Once you've got enough data to reliably survive that kind of situation, you're 90% of the way there.