[Tagging] Access tags applying to higway=construction and ones that will apply to completed way

Paul Johnson baloo at ursamundi.org
Wed May 26 19:29:46 UTC 2021

On Wed, May 26, 2021 at 10:35 AM Mateusz Konieczny via Tagging
<tagging at openstreetmap.org> wrote:
> Typical cases include:
> - (1) sidewalks mapped with tag on road itself - and just carriageway is closed

If separated by kerb, then this is a good time and a good excuse for
moving the sidewalks to their own ways.  Otherwise,
construction=minor, motor_vehicle=no.

> - (2) major reconstruction, there is a path across construction site to allow people
> to access their homes - as side effect pedestrians can walk across entire construction
> site

Consideration should be given to map a temporary roadway with the
appropriate access through as highway=service, access=destination,
foot=yes with a note indicating its temporary nature.

> - (3) sometimes it is impossible to keep road driveable for cars but it is possible
> to put planks/rubber mats/concrete plates/walkways to keep it passable for
> pedestrians and sometimes also for cyclists

Same as above but highway=path for the temporary access.

> Mapping road under construction in the same way as road with just closed vehicle access
> is problematic because
> - it is tricky and unusual to handle it in this way
> - for some edge cases (routing of emergency vehicles) it actually does matter
> - it is much easier to detect road for resurvey ("is construction complete") with
> highway=construction tagging

I don't see a reason why opening_date=* couldn't also apply to
construction=minor situations.  Or a good reason why, say,
highway=construction, construction=* should be routable to anything
that isn't a construction vehicle.  If the road's completely open
without work being done to it, then no construction tag. If it's being
worked on but is in any way routable, construction=minor.

If it's completely out of commission or yet to be opened,
highway=construction, construction=* (where * is whatever the highway
tag will be once it (re)opens); this is completely inaccessible if
you're not part of the DOT working on it.  highway=construction
*really should* override any access tags.  It's also  basically ideal
for maintainability, since all the original state is still there.  All
you have to do in JOSM or id to reopen an object or series of objects
is drop opening_date=* and highway=*, then change construction=* to
highway=*, which can often be done in one single selection quite
easily.  For complex situations where a road is being moved in stages
(such as an interchange being replaced or in regions where the DOT
repaves the highway by using an extra wide right of way, paving up a
second carriageway, and then removing the original), this is also
preferable as it allows the new alignment to be mapped and staged.
Then as the job progresses, make the appropriate joins and splits,
remove demolished segments and retag the newly opened ones, in a
reasonably straightforward manner.

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