(209-2) Stories about 'Falling Rocks Ahead'
The warning sign 'Falling Rocks Ahead,' commonly seen on roads in mountainous areas, often prompts people to ask, 'What exactly am I supposed to watch out for?' This article explains the meaning of this warning sign and some stories behind its design.
If you're told to 'watch out for falling rocks,' what should you be watching for?
On roads in mountainous areas, where steep cliffs rise up along the roadside, 'Falling Rocks Ahead' warning signs are often installed. Even in deep mountain areas where other warning signs like speed limits or 'Watch out for animals' are not present, these 'Falling Rocks Ahead' signs are frequently found.
Regarding this sign, as the design suggests, some people ask, 'Do I have to drive while dodging rocks falling from the cliff like in a video game!?' What is the truth of the matter?
The Sign Ordinance provides guidance on where to install them, as follows:
On the left-hand roadside, at a point between 30 and 200 meters before a location recognized as requiring caution for road traffic due to the risk of falling rocks.
Regarding the content of 'Falling Rocks Ahead,' the Ministry of Land, Infrastructure, Transport and Tourism (MLIT) website contains the following statement:
It does not mean that you only need to be cautious of either 'falling rocks (boulders)' or 'rocks (boulders) that have already fallen onto the road.'
In other words, you need to pay attention to both rocks/boulders that are falling and rocks/boulders that have fallen onto the road. However, statistically speaking, it is more likely that you will encounter a situation where rocks/boulders have already fallen and are scattered on the road surface than that you will encounter the moment they are falling.
Warning signs in the same category
Looking at the list of road signs from the Ministry of Land, Infrastructure, Transport and Tourism, the three signs 'Slippery Road,' 'Falling Rocks Ahead,' and 'Uneven Road Surface' actually all share the same serial number 209. What they have in common is that they all represent 'warnings regarding road surface conditions.' Historically, in 1967 (Showa 42), the two signs 'Falling Rocks Ahead' and 'Uneven Road Surface' were added to the 'Slippery Road' category.
Stories about design variations
There are several interesting things about the design of the 'Falling Rocks Ahead' warning sign if you look closely, so let me introduce them.
Number and shape of the rocks
If you look at various 'Falling Rocks Ahead' warning signs, you will notice that the number and shape of the rocks, as well as the shape of the mountain, differ. In fact, the detailed design varies depending on the road administrator.
(Top left) Most common design, (Top right) Narrower mountain
(Bottom left) Large round rock, fourth rock embedded in the road
(Bottom right) Large round rock
Actually, in the latest list of road signs and Sign Ordinance designs from the Ministry of Land, Infrastructure, Transport and Tourism, there are three rocks, and the mountain from which the rocks emerge is not chipped.
On the other hand, the National Police Agency's Rules of the Road show four stones, which are round and large.
Looking at the signs actually installed, the number of stones is almost always four.
Symmetrical design
The 'Falling Rocks Ahead' warning sign is defined with a design showing a mountain on the left and rocks falling on the right. While a symmetrical design is not officially defined, looking at installations on the road, when there is a cliff on the right side of the road, a symmetrical design with the mountain on the right is often used.
Avalanche Warning
As a variation of the 'Falling Rocks Ahead' warning sign, there is an 'Avalanche Warning' sign in heavy snowfall areas. This has various designs.
There are various variations
Combination with Animal Warning
On Chichijima in Ogasawara Village, Tokyo, there is a falling rock warning sign combined with a feral goat animal warning sign.
Warning for a section
Since falling rock warnings are needed for sections where cliffs continue, they are sometimes used together with auxiliary signs such as '(505-B) Start', although this is not officially defined. (However, there are almost no signs for within the section or the end of the section.)
On national and prefectural roads managed by Hiroshima Prefecture, driving caution levels 1 to 4 are set for sections with risks such as falling rocks. Level 4 is described as a 'section with a high risk of falling rocks or landslides'.
A rare example installed together with '(506) Within Section'
Extra edition. A falling rock warning sign integrated with a delineator post (fixed visual guidance post).
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Please take a look at this as well.