GP's comment makes more sense if you consider driving safely/legally and actually navigating to be separate problems. in general, this is a good way to look at it; misunderstanding right-of-way is much more serious than taking a wrong (but legal) turn.

there are some cases where there is an implied state/town speed limit, but other than that, all the information you need to drive safely/legally is on signage in front of you or a hundred feet back.