What Is A Dangerous Stretch Of Road?

[VUB]

I'm planning a trip to Tuscany next year and have initially used the Michelin road planner, from Calais to Florence.

http://www.viamichelin.co.uk/web/Routes

On the way it warns of a "dangerous stretch of road" a number of times for distances in excess of 90km. But I cannot find any definition of what they mean by a dangerous stretch of road. For example, it
states that the N59 is dangerous, but looking at a map I can see nothing that might be a problem.

Apart from high mountain passes, what could possibly be classified as dangerous for 100's of kilometres?

[leyorkie]

IT is illegal in France to identify the locations of speed cameras, dangerous sections usually have a safety camera along that stretch of road.
Your sat nav indicates dangerous road sections

[Fastdruid]

It's got corners on it.