How to map that LED-displayed speed limit is not really variable?

General talk Tagging general discussion
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It is nasty to survey, but once you were at specific location multiple times it is possible to mark that sign with dynamic speed limit display is always, all the time, displaying the same value.

Do we have way to mark this, beyond putting it into note ?

See Key:maxspeed:variable - OpenStreetMap Wiki

2

More context needed. It’s not =obstruction ? You would need to check when there’s incidents.

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Yeah, unless the conditions are signed (or documented on some municipal web etc) it is basically impossible to say. Just because one passed 100 (or 1000) times and it always had the same value, does not mean it is not variable. You can’t really[1] prove such a negative…

However, if it were always intended to show same fixed value and absolutely never ever change, it would more likely be regular simple metal sign; instead of piece of finicky electronics which needs maintenance, power, remote control, operating procedures, etc.

Well, there is some use of (undocumented) maxspeed:variable:default which seems to be about marking a default value (e.g. what it will show most of the time).

There are also maxspeed:variable:min and maxspeed:variable:max, and when set to the same value it would indicate that the value never changes, but as noted unless they are published by appropriate governing body, they are unverifiable, thus problematic to use in OSM.

If not published, I’d stick to note=* for personal guesses (e.g. “I’ve passed here dozen times each day from 2021-2024, and it has always shown 50 regardless of rain, snow, time of day, warnings about air pollution or lack of them, and even through 12 smaller and 3 bigger accidents on the road ahead” - or likely something less ambitious depending on your exact experiences, of course).

That being said, I find that wiki problematic more generally. While maxspeed:variable=yes (which is AFAICT what one should mark if it is unknown in what situations the limit shown might change, i.e. your case) seems fine and as one would expect, the wiki then proceeds to say (much to my dismay) that maxspeed:variable=no is basically the same thing as yes, i.e. that:

Fixed limits can still vary depend on conditions, e.g. time of day.

:exploding_head:

Wait, what? How can one call it fixed if it changes several times a day?! I mean, by that logic, one can define anything that is variable as “fixed”, if one only would apply the meaning of the word to “dt” (infinitesimally short amount of time).

Or what am I missing?

For me, maxspeed:variable=no would rather mean either:

  • it is a fixed piece od dumb circular metal sheet with speed limit permanently painted on it, or
  • it is electronic LED speed limit, but the governing authority has published (on the site, or on their web) that it never changes (for the time being, i.e. they reserve the right to make changes at some time in the future. E.g. they might make it change values several year later when they complete some further step of the project and get funding for controlling circuitry. Or they’ve made it electronic only for better visibility in night/fog, and there is no remote control circuitry at all).

  1. well, I suppose one can disassemble the device, and/or reverse engineer the microchip, but I’m trying to be practical here… ↩︎