[Tagging] Road hierarchy

Kevin Kenny kevin.b.kenny at gmail.com
Thu Aug 8 20:25:04 UTC 2019

On Thu, Aug 8, 2019 at 11:12 AM Peter Elderson <pelderson at gmail.com> wrote:
> We're on the same page. The pavement and separations argument just illustrates how local authorities may make the same distinction, and try to regulate traffic and safety informally. So here, I can use this for the classification, but in the next town it would probably not work.

We're stuck with the hierarchy, but it doesn't really work that well
in most places other than the UK.

In my area, there actually is a reasonable hierarchy that reflects the
relative importance of routes:

motorway - Interstate, US, and State highways that are dual
carriageways with fully controlled access. (Some of the State Parkways
fall in this category but are named and not numbered.)

trunk - some few special cases where a multi-lane dual carriageway is
only partially grade-separated from local traffic, or a 'super two'
where a single-carriageway road is grade-separated from local traffic,
with acceleration and deceleration ramps like a motorway.

primary - my state designates most US Highways and some numbered state
touring routes as primary

secondary - other state touring routes, numbered and bannered.

tertiary - state reference routes, or numbered and bannered county
highways. State reference routes get an ┬┤unsigned_ref=*┬┤ since the
only field-visible marks of the numbers is a roughly 20x20 cm sign
showing the number and chaining. These markers have three four-digit
rows rows and are next to impossible to read from a moving car. Many
are collector roads that are prominently bannered, "TO NY 7", "TO US
20" etc.

The lower classifications are harder. We have had many arguments about
the boundaries, in rural areas, between 'unclassified', 'residential',
'service' and 'track'.  When you get into the North Woods, New York
has some public highways that are Pretty Darned Bad - I'm pretty sure
that I've tagged a "highway=track abandoned:highway=tertiary
surface=compacted tracktype=grade4 smoothness=very_bad" and decided,
"No, I'm not driving my Forester on this before scouting ahead." On
that particular road, there were indicia that would support any of the
five classes from 'tertiary' to 'track'.

I've also put reference numbers for the highway system onto
'highway=footway' - for roads that have been washed out or destroyed
in rock slides, where the bannering indicates a numbered route, the
actual route is marked with 'detour' signs, but the condition is
semi-permanent because there's never funding to rebuild the road.
There's actually a blazed long-distance hiking trail that follows some
of these sections, so 'footway' is appropriate, but the sections I
have in mind are impassable to anything on wheels.

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