Addition of a road type: Dangerous or Unsafe road
It is suggested to add one more road type: Dangerous or Unsafe road. This type will be used for example when it is a very steep or winding or bumpy road, or a road on the edge of an abyss.
The time it takes to pass the road in such cases is not the only parameter that counts.
It is suggested that the "penalty" for passing such a road will be proportional to its length. For example 1 minute for every 100m.
Daniel Weishut commented
Excellent idea! Though I'm a good driver, I have found myself occasionally in situations in which I probably would have not taken a certain road, had I known in advance it is that dangerous. This happened to me both with a very steep road and with a curving road with on one side a valley.
Alternately, perhaps segments could be marked as "difficult" the way turns can be marked now. Then, the user's decision on whether to be offered difficult routes could apply to difficult segments as well as turns.