[Tagging] RFC Update - Hazard Proposal - rock/land fall/slide

Kevin Kenny kevin.b.kenny at gmail.com
Fri Dec 4 01:02:29 UTC 2020


On Thu, Dec 3, 2020 at 12:54 PM Mateusz Konieczny via Tagging <
tagging at openstreetmap.org> wrote:

> I am not exactly happy about "rock slide" as it seems weird to use it where
> danger is primarily about individual rocks dropping, not about full scale
> rock slide.
>
> Personally I would prefer "failing rocks" for warning used by a standard
> road
> sign.
>
> (difference is minor, but if we have luxury of selecting any value...)
>
> Disclaimer: I am from a relatively flat country, maybe this sign warns
> about
> full scale rock slides elsewhere?
>

You are a flatlander, aren't you?

Around here, before the international iconography was adopted, the signs
always said, 'fallEN rocks'.  There's precious little a driver can do about
fallING rocks, but incidents of being under them are vanishingly rare.
Instead, the real hazard is fallEN rock blocking the roadway. (Even now,
the MUTCD W8-14 sign prefers the sign with the English words
http://www.trafficsign.us/150/warn/w8-14.png, although some states,
particularly near the Canadian border, favor the pictorial one
https://www.usa-traffic-signs.com/v/vspfiles/photos/cust_W8-14-2.gif that
suggests, incorrectly, that fallING rocks are the chief hazard.)

Around here, also, the stone is sedimentary, often consisting of layers of
soft shale or dolomitic limestone interspersed with much harder sandstone.
The shale erodes away from underneath in a valley or highway gut, until the
sandstone on top of it can no longer support the weight of the overhang and
collapses,  It has little enough structural integrity that you don't
generally get single rocks falling, you get a pile of talus and debris.
Sometimes it's a five minute job with a skid-steer to push the stuff away.
Sometimes it's a couple of weeks with many vehicles to clear away a huge
mass of material and rebuild the shattered pavement underneath.

On Thu, Dec 3, 2020 at 1:09 PM Paul Allen <pla16021 at gmail.com> wrote:

> That's not to say we don't have landslides in the UK, but it appears
> we don't construct roads in places where they are anticipated to
> happen.
>

The idea of "we don't build where the rocks might fall in the road" doesn't
work all that well when every mountain pass poses the same risk.
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