[Talk-GB] Maxspeed tagging for the UK

Chris Hill osm at raggedred.net
Wed Apr 6 15:02:29 BST 2011

On 06/04/11 14:22, Peter Miller wrote:
> Do we have a preference for tagging unrestricted limits in the UK? I 
> say that because a section of the A1 is beginning to look a bit war 
> damaged  (as in edit war).
> It started with maxspeed=national. I changed it to maxspeed=70 mph. 
> Christcf then added a 'source:maxspeed = UK:nsl_dual' and also 
> 'FIXME:nsl = inferred dual-carriageway NSL - remove this tag once 
> verified; if this is a Special Road, remove the source:maxspeed tag 
> and add motorroad=yes'. And now c2r has changed maxspeed back to national!
> Here is the way in question:
> http://www.openstreetmap.org/browse/way/3994397/history
> My preference is to put a numeric speed in the maxspeed field and 
> something like 'UK:nsl_dual' in source:maxspeed field, however I am 
> not that keen on a prolonged edit war on this and want to gauge wider 
> opinion.
> If it is ok to put something like 'national' in the maxspeed field 
> then what text options are appropriate for the UK? 'national' seems 
> too vague. 'UK:national' or 'GB:national' would fit with the 
> recommended structure as would 'UK:motorway', 'UK:nsl_dual' and 
> 'UK:nsl_single' however I can find no guidance on that.
> Assuming we are supporting these second format then where should the 
> look-up table be that gives the values? This page is having a go at it 
> but doesn't seem to be doing a very good job!
> http://wiki.openstreetmap.org/wiki/OSM_tags_for_routing/Maxspeed
> Incidentally, I have also updated the key:maxspeed wiki page so that 
> it more clearly represents the tagging recommendations and options 
> available, in particular it presents the two options for encoding 
> implicit speed limits well. Can people see if they agree with current 
> representation of opinion.
> http://wiki.openstreetmap.org/wiki/Key:maxspeed
> Any thoughts?
I think we should tag what we see on the ground. The sign is national 
speed limit, not 60 or 70 mph. The black & white sign does not mean 60 
mph or 70 mph for every vehicle, lorries have lower limits for example. 
I currently don't tag maxspeed on national speed limits, but this 
absence encourages the nonsense that chriscf came up with, so if pushed 
I'd use maxspeed:national . All of the roads being discussed are in the 
UK, so they do not need UK: or GB: namespaces. This is a geo-database 
after all.

Cheers, Chris
user: chillly

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