[Tagging] Sample tagging for highways with no lane markings

Martin Koppenhoefer dieterdreist at gmail.com
Tue May 22 16:26:38 UTC 2018

2018-05-22 17:18 GMT+02:00 Tod Fitch <tod at fitchdesign.com>:

> In reviewing the wiki in preparation to fixing some of my older mapping,
> it seems there is an inconsistency in how to tag a road that is wide enough
> to two lanes of traffic but is lacking lane striping.
> In the lanes description [1] it says "the lanes=* key should be used to
> specify the total number of marked lanes of a road." But in the out of town
> highway tagging sample page [2] with a photo described as "smaller road,
> maybe tertiary with appropriate administrative status" it shows a lane
> count on a road with no markings.
> Am I correct in believing that the example photo should have its tagging
> changed, dropping the lanes=2 and adding a width tag (if the width is known
> or can be reasonably estimated)?

>From practise in my area I would think we should drop the requirement of
road markings and leave more freedom to the mapper. If a road is wide
enough for 2 lanes and traffic is using 2 lanes, but there are no road
markings, or currently no road markings, or mostly no road markings, I
would still tag allow to tag 2 lanes. We could add a tag about road
markings, or maybe absence of road markings.
I'm unsure whether to differentiate absence of road markings because they
are not deemed necessary from absence where they once were there but are
not visible any more and someday might return.

For example on a typical provincial country road with clearly 2 lanes there
will often be no markings. (IMHO lanes=2 as it would be implied also when
not setting a lanes tag), while in another case the situation is more
ambiguous. This is a primary with a wide dual-carriageway, where 2 cars
sometimes fit, while sometimes would require the slower driver to drive on
the shoulder (what actually happens) so the other can overtake. I would be
reluctant to tag these roads with 1.5-2 lanes (unmarked) as lanes=2 (in OSM
it is indeed one lane).

references, case A: https://www.openstreetmap.org/way/487717815
case B: https://www.openstreetmap.org/way/90537120
if you pay attention on google you can see how it is used as 2 lanes and
even a car surpass:

We've also seen the example of the residential area in Australia where only
the intersections had road markings.

> My current interest is in fixing the tagging for residential roads that
> are wide enough for bi-directional traffic with legal parallel parking but
> have no markings on the pavement. I don't see a exact match to that in
> either the urban [3] or rural highway [2] tagging example pages.
> To use the street I live on as an example, am I correct that a residential
> road with bidirectional traffic and parallel parking with no markings
> should be tagged as:
> highway=residential
> surface=asphalt
> parking:lane:both=parallel
> width=40’0"
> maxspeed=25 mph

to me this seems lanes=2

> If, and only if, a center strip is added then lanes=2 should be added. (I
> actually measured the width in this case but for hope to be able to use the
> measurement tool on aerial imagery in JOSM for most cases).
> Is my current understanding correct?

it is the literal reading of the lanes tag description, but as you pointed
out, it conflicts with other parts of the wiki. And if you don't add a
lanes tag, the common default is lanes=2.

What do you think about a new tag for the absence of road markings?

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