I don’t disagree with your premise, but the word safe doesn’t apply to even mapped roads.

“Safe” changes on a daily, even hourly, basis. An unrelated accident changes the Safety of a particular route. A rainstorm can surface oils from the road, making it unreasonably slick for a short period of time. A crew working on the sewers can change the routing of a road onto the shoulders, which will have different grip characteristics than the road itself.

Even Arizona can see snow.