
Decoding Utility Markings Spray-Painted on City Streets - deadbunny
https://99percentinvisible.org/article/colorful-language-decoding-utility-markings-spray-painted-on-city-streets/
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rkowalick
A coworker of mine shared this neat little book which contains, among other
things, descriptions of a lot of the internet infrastructure markings one can
find on the streets of NYC based mostly on the author's own observations:

[https://www.amazon.com/dp/B018CH0MX2](https://www.amazon.com/dp/B018CH0MX2)

Definitely something I had never really thought about until recently.

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robbrown451
I see a lot that say "USA". Always curious what that means. Presumably not
United States of America. (this is in California)

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lwf
It indicates that the markings were made by Underground Service Alert, the
entity that's on the other side of 811.

c.f.
[https://en.wikipedia.org/wiki/Underground_Service_Alert](https://en.wikipedia.org/wiki/Underground_Service_Alert)

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Ibethewalrus
Thanks!

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ggm
The European standards for pipes as formal plaques on the wall, and the UK one
which uses a different notation and premade concrete stub-sign at ground level
had me fascinated.

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jahewson
Here’s some examples of the UK signs:

[https://www.plateandlocate.com/article/1/name/Buried-
valves-...](https://www.plateandlocate.com/article/1/name/Buried-valves-and-
pipelines-identification)

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ggm
Oh they're far more modern than I was used to.

[http://metricviews.org.uk/wp-
content/uploads/070-rc.jpg](http://metricviews.org.uk/wp-
content/uploads/070-rc.jpg)

was what I was expecting. Glad they've gone metric and modern.

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irrational
I was putting in a gate once and had them come out to mark the utilities.
There was a gas line running through the area, but it was marked at 3 feet off
from where I was digging the post holes. When we pulled the auger out of the
ground I noticed the gas pipe right on the very edge of the hole. I'm still
not sure how the auger didn't cut through it. I'm also not sure how they
managed to be so far off the mark.

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jaclaz
Anecdata, but I worked several years in infrastructure projects (and in the
course of that cut numberless pipes, cables - both electricity and
communications - and what not), the basic issue in my experience was the
sloppyness with which the drawings of the utilities layouts were made or the
use of "unreliable" references.

A typical one, is the indication (on the drawing) that a cable is 30 cm from
the border of the sidewalk, but in the - say - 30 years since that cable was
laid down the sidewalk has been enlarged by 40 cm AND a new cable has been
laid down at 30 cm from the new sidewalk AND this other new cable has not been
added to the drawing (or it has been added to another drawing by mistake).

So you go there, actually find "a" cable 30 cm from the sidewalk, believe in
good faith that it is the one on the drawing, and next minute you cut the one
now under the sidewalk.

It is only a few years that GPS positioning is used for cable and pipes layout
(which should give better "absolute positioning") but the issues about mis-
labeling and mis-reporting (given also the number of different companies,
particularly telecommunications ones that may lay new cables) have not changed
much AFAIK.

We once had a set of bored piles (Ø 1000 mm) for the foundation of a
sustaining wall miss a high pressure large diameter (Ø600 mm) methane pipeline
by _millimeters_ (the drilling rig bit the steel pipe covering, making the
actual metal of the pipe shiny).

The explanation was that the people making the drawing and maintaining the
pipeline took as reference the milestones of the road (that were replaced
because a curve was added some kms before and shifted by 100 m) and gave our
project the green flag because we were almost 100 m away from the pipeline.

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Jaruzel
As UK'er my first thought was 'Are the UK colour codes the same?'

And yes, They are!

[https://www.cornerstoneprojects.co.uk/index.php/blog/undergr...](https://www.cornerstoneprojects.co.uk/index.php/blog/underground-
utility-colour-codes/)

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Neil44
I didn't undestand why they said that diggers are on their own in the UK, and
then in the next paragraph went on to talk about the UK's colour codes. It
seemed like a contradiction.

I have a client who does groundworks and they always know when there's
supposed to be something down there. You use the detectors to double check not
as your only source. There could be something down there that's old and not on
the registry or that HV power cable could be a few feet to the left of where
it's supposed to be.

When you're the man taking a circular saw to the pavement and your boss is the
one paying for the repairs, you check!

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symplee
For markings of such importance, you'd think they would have a standardized
stencil. The video of the worker spray painting seems a little too nonchalant,
potentially opening the door to misreading. And if standardized, there could
even be a digital reader (like an OCR?) to tell others exactly what it means
in the event of confusion or differing interpretation.

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notable_user
There’s not many options for what it could be, so it’s pretty easy to figure
out. The color is most important, with some additional info like utility
(which are few and welol known) and width.

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symplee
I wonder how they factored in that red-green color blindness affects up to 8%
of males. Should color really be the most important? Would be interesting to
see what percentage of accidents are attributed to misreading a symbol vs a
color vs anything else.

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mjevans
It's probably old enough that they didn't. Plus as said elsewhere, where NOT
to dig. If looking to intersect it someone who can see the color correctly
will have to identify the location.

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bcheung
Really hard to read that chart. The font is like 4 pixels tall total with
massive compression artifacts.

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rootbear
I clicked on it and got a bigger image that was easier to read.

