Whenever I see a sign like this, I think, "Gosh, it's great that they're warning me, but I'm not too sure what I'm supposed to do now that I've seen the sign." (In case you're not familiar with this sign, it means: "Beware - possible rock falls.")
Should I turn around and take another road instead? Not practical, no. Should I keep a lookout to my right, watching for large boulders rushing down the mountainside, so that I can take evasive action into the sea? Tricky and potentially dangerous - I might mistake a mountain goat for a boulder for instance, and plunge to an unnecessary watery death in my haste to get away from it.
Maybe they're actually just cruel, and really mean for me to drive this stretch of road with paralysing fear as my navigator. What do you think?