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I'm from Flanders and I don't have a driver's license. These signs are rather rare in Flanders, but I see them frequently as a passenger alongside the Spanish coast, in the Valencia province.

The thing I don't understand: what does this sign mean? That there might be rocks falling on your car? You don't know when they're going to fall, so you can't adjust your speed for it. Rocks might lie on the road? You'll see that anyway.

How should you adjust your behavior around these signs?

  • 17
    "Rocks might lie on the road? You'll see that anyway." you'd be surprised by what some people won't see if they aren't looking for it. And I am not even excluding myself here - I once almost drove into a rock because I did not expect one to just lie on the street.
    – YviDe
    Commented Nov 5, 2015 at 13:00
  • 14
    I think the idea is to be aware that rocks may be lieing ont he road, and be prepared for obstructions when cornering/cresting/etc
    – CMaster
    Commented Nov 5, 2015 at 13:11
  • 2
    The sign is an advisory, so there are no 'rules' to follow. But CMaster is right. I used to wonder about that too. Commented Nov 5, 2015 at 14:08
  • 1
    See also the discussion starting with this post.
    – msh210
    Commented Nov 5, 2015 at 19:26
  • 11
    In my country it means caution: spontaneous crust-first pizza disintegration area. Generally you should finish your pizza first, or at least eat it defensively and maintain awareness of the crust state. Pizza delivery drivers are encouraged to find an alternate route.
    – Jason C
    Commented Nov 6, 2015 at 7:06

6 Answers 6


Basically it is a warning of the potential for rock falls. Two warnings built into one, 1) rocks could being falling into your path or on your vehicle 2) rocks could have fallen and maybe on the roadway ahead.

Your actions should be to watch not only the normal driving issues, but also keep your eyes out for rocks that maybe be present on the roadway or falling. If the road is winding with short vision distances, then slowing down is warranted.

  • 12
    ...and 3) rocks might be in the path of oncoming traffic. I narrowly missed a head-on collision one time when a huge speeding truck going the opposite direction drove over a rock in the road while cornering, causing it to slip across into my lane almost head-on into the vehicle I was in. Luckily my driver saw this coming (or, had amazing reflexes!) and swerved just in time to avoid it Commented Nov 5, 2015 at 16:56
  • Edited number 2 to better describe what I meant.
    – user13044
    Commented Nov 6, 2015 at 1:27

I have to add another very important point that is not listed so far: When you see this sign you should also avoid any unnecessary stops to decrease the chances to bet hit by rocks. This is in particular the case when you see this sign on hiking paths in the mountains. The sign is not only used on roads but also paths. It's not really a law though, but you should really follow this recommendation.

Here is a good example with text in English, German and French:

enter image description here

  • 4
    I don't think it's an important point (very or otherwise), it's a different meaning for this sign in a different context (namely when you are hiking, on foot). The OP has no reason to be wary of stops when driving, in this context, it's really about rocks lying on the road.
    – Relaxed
    Commented Nov 5, 2015 at 20:31
  • 14
    I don't agree. I wouldn't park my car on a road that has this sign. You dramatically increase the chances that your car gets hit by a rock. Granted, in a car it might probably not be deadly, but still it will cost you at least a lot of money. Commented Nov 5, 2015 at 20:38
  • 4
    But the most important point is that it's confusing to conflate both signs. When hiking, rocks on the ground are a non-issue and rocks falling (especially because someone in front of you moved them) is what the sign is about. By contrast, on mountain roads, falling rocks are still very rare (otherwise the road would have to be closed and protected) and the sign is about stones lying on the ground.
    – Relaxed
    Commented Nov 5, 2015 at 20:44
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    And do the stones grow on the ground? No, they have to fall down, otherwise there wouldn't be any stones on the road in the first place. Commented Nov 5, 2015 at 20:45
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    You're being disingenuous. Of course they have to be falling but there was a serious risk or large rocks falling, you could not keep the road open and be happy by putting a sign! It's not what it is about. The problem is that this confusion leads to the silly advice someone else posted about driving quicker… It's very important to understand that we are dealing with two different meanings of the sign, which call for different behaviours.
    – Relaxed
    Commented Nov 5, 2015 at 20:54

This signal is just a warning sign. It's information about a possible danger. You're not supposed to do anything in particular as rule. You should assume a defensive position against this event though. Whatever that means it's up to you. Locals may know about it, but you, that come from a flat land, wouldn't even suspect. There are many of these signs, that I learned in driving school, and I never saw in real life. Not all dangers are everywhere. Sometimes, when travelling one pops.

You might think it's very useless but take this example:

Imagine I aproach you and I slap you by surprise in the face. What would your reaction be? You would be completly surprised - you could run away afraid or you could even react in surprise and do the same. But I did slap you. Or maybe I just caught a mutant bug in your face that was about to kill you. You don't know!

Now, imagine someone warns you I can slap and I approach you with the same intention? what would you do? you would be prepared and could react properly!

It's the same here. You will have a more defensive attitude towards falling rocks or rocks on the road. You should assume both situations are possible. If at night, with wind or rain you will probably want to drive slower or you might even drive at the same speed if confident enough, but you will be aware of the rocks. If some fall or you hit one with your car you know what happened and will probably react in a more appropriate way. If caught by surprise you could react in unexpected ways and cause a larger accident by driving off road or against another car.

To conclude: this kind of information is very important to make you aware of possible dangers that otherwise you wouldn't know of. You should than adapt your behaviour accordingly to the risk, considering external factors as well like wind, rain, visibility and traffic conditions, but it's up to you to decide.

If you're puzzled with that sign you should look at this one, it's my favorite:

various dangers

This is also a danger sign, and basically means "various dangers". You should basically prepare... anything can happen! :)

  • I wonder how you imagine a "defensive posture" against falling boulders to look? Commented Nov 6, 2015 at 23:50
  • @LightnessRacesinOrbit It depends on the road and local conditions. There is no unique answer and thats why the code does not specify it. Anyway if the rocks are that big and the risk so eminent the road should be closed!
    – nsn
    Commented Nov 7, 2015 at 7:46
  • 1
    @LightnessRacesinOrbit: I don’t know a defense against falling rocks, but against the risk of fallen rocks in the road, I would just drive a little extra-cautiously.
    – PLL
    Commented Nov 8, 2015 at 23:43

Rocks normally fall onto a road in two situations:

  1. A freeze-thaw or heat/cool cycle has forced the rock out of place, causing it to fall.
  2. Rain or flowing water has washed away dirt supporting the rock.

Because of this, most rockfalls occur during the early morning or during/just after rainstorms, particularly during the cooler months. If you're driving during a sunny summer afternoon, there's no real risk. On the other hand, during a rainy fall morning, you should slow down and keep an eye out for rocks lying in the road (I once encountered a half-ton boulder under these conditions). In either case, the odds of being struck by a falling rock are very low.

  • 1
    +1 especially for the last sentence as it seems there is a lot of confusion about this.
    – Relaxed
    Commented Nov 6, 2015 at 0:30
  • 3
    Sorry but the risk of fallen rocks still being in the road is very real at ANY time of day. To assume they only are present under certain conditions or time of day is asking for trouble.
    – user13044
    Commented Nov 6, 2015 at 1:32
  • 2
    @Tom: Mark has not stated that the risk is absent at particular times. His description is very accurate. Erosion is a geological process that obeys the laws of physics, not an unknowable risk that requires equal precautions under all conditions.
    – user5017
    Commented Nov 8, 2015 at 21:06
  • @BenCrowell - "If you're driving during a sunny summer afternoon, there's no real risk" - that sounds to me like he is saying risk is absent. And I never disputed his explanation as to why rocks fall, I have known that to be a reason most of my adult life. But as someone who frequently travels by road in the mountains, all over the world, I know that rocks can be present without warning even on sunny afternoons. And to pooh pooh a warning is a sign of an immature driver.
    – user13044
    Commented Nov 9, 2015 at 3:42
  • @Tom, driving during a sunny summer afternoon, you can also encounter a broken-down car, wildlife, or other obstacles in the road. The odds of encountering a fallen rock in these conditions is low enough that you don't need to take unusual precautions.
    – Mark
    Commented Nov 9, 2015 at 8:48

The German road code just specifies it as a warning sign. Source (the sign is called "Steinschlag")

That means there are no specific rules attached to this sign, but in the interest of their own safety, people should pay extra attention. The general road code already specifies that people have to drive carefully, the signs in that list are just reminders, drawing special attention to road conditions.

Specifically, Steinschlag is not listed in Anlage 1, StVO §40 which further specifies some warning signs, nor Anlage 2 to 4, where signs having an effect on road rules are listed.

I can find no indication that this is different in Spain, but I'm also not Spanish. Not all traffic signs in the EU mean the same thing when it comes to road rules.

  • This probably goes too much into individual situations and clauses, but in case your car gets damaged by either a rock falling on you or you driving into a big rock, does this warning sign have any effect on how your insurance will handle paying the damage?
    – Nzall
    Commented Nov 5, 2015 at 15:04
  • I couldn't find any indication for that for Germany, but here we also use "steinschlag" as the term for when a small stone breaks the glass of your windshield, so searching is not that easy
    – YviDe
    Commented Nov 5, 2015 at 15:07

In a nutshell: Yes, it's about rocks lying on the road and no, you might not always see them, especially on mountain roads with many bends. So it's a warning to adjust your speed (i.e. drive more slowly) and be generally alert in places where the risk is higher. As someone who has a lot of experience driving in mountain areas, I can tell you that it is useful.

The Vienna convention on road signs and signals describes the sign thusly:

  1. Falling rocks

Warning of a section of road on which there is danger from falling rocks and the consequent presence of rocks on the carriageway shall be given […]

Also, to clarify: It's not mainly about huge rocks blocking the road and stopping your car but simply stones that are big enough to cause some damage or prompt you to make a dangerous manoeuvre if you see them too late.

Incidentally, because there seems to be a lot of confusion about this in the comments and some of the answers, it's easy to realise that the sign is mainly about rocks lying on the ground. Any falling rock will represent a danger for a few seconds and then lie there for hours if not days, and many more motorists will be exposed to it lying on the road rather than falling.

If there were so many rocks falling that spending a few extra minutes in the area would matter, the road would be extremely unsafe and literally covered in stones to the point that is is not usable. As @Mark aptly put it in his answer, “the odds of being struck by a falling rock are very low”. Speeding up to reduce that risk is a very bad idea, you should slow down.


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