[Tagging] maxspeed:signed=no - new proposed tag

Martin Koppenhoefer dieterdreist at gmail.com
Thu Jan 7 13:28:44 UTC 2021

Am Di., 5. Jan. 2021 um 02:48 Uhr schrieb Minh Nguyen via Tagging <
tagging at openstreetmap.org>:

> source:maxspeed=* seems capable of indicating the presence of a default
> speed limit, since apparently the "<country_code>:<context>" syntax is
> only for unsignposted speed limits. [1] But in the scenario Mateusz
> describes -- an intrepid surveyor tags a street beforehand to flag it to
> armchair legal analysts -- how would the surveyor know which context to
> assign? Also, wouldn't it be strange to see source:maxspeed=* on a
> feature without maxspeed=*?

they would not know which context applies and would set the tag. From the
missing maxspeed and source:maxspeed, someone else can see that information
is missing and could check it on the ground. Maxspeed is not something that
should be done by armchair mappers (save the case that there is sufficent
and recent coverage of (non-google) street view data, mapillary etc.).

> The "<country_code>:<context>" syntax is also overly simplistic. It's
> telling that no one has attempted to extend the table at [2] with values
> for the U.S. Each state has plenty of default speed limit contexts, some
> of which defy the OSM tagging model. [3]

this has been brought up several times, but someone would have to actually
add it to the wiki ;-)
I have no idea, and have limited my actions to places where I am well aware
of the situation.

> Not everyone who surveys for OSM does so behind the wheel or even has a
> driver's license. Not many data consumers can consult a local licensed
> driver for the correct answer on demand. ;-)

they can simply omit the information. If someone has no clue about the
legal situation, they should avoid adding tags that describe this aspect of
the situation.

> Even someone who does drive may not have a full grasp of default speed
> limits in their jurisdiction.

it still boils down to you cannot add what you do not know. Adding that you
do not know it on the other hand, does not seem helpful either. If you do
not know the limits, they are maybe not so important in your area? ;-)
If you are able to recognize a maxspeed sign, you could add this
information, although I would say its usefulness is limited if you cannot
tell as well, what the implications are. E.g. maxspeed:signed=no (I would
not encourage maxspeed:signed=yes, as it is already tagged with

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