[Talk-GB] Maxspeed tagging for the UK

Peter Miller peter.miller at itoworld.com
Tue Apr 12 10:50:44 BST 2011

On 12 April 2011 10:32, Steve Doerr <doerr.stephen at gmail.com> wrote:

> On 11/04/2011 23:39, SomeoneElse wrote:
>  Great - someone has now changed a bunch of "maxspeed=national" locally to
>> me to to "maxspeed=60 mph".  Next I guess someone will come along and add
>> "source:maxspeed=i_was_sat_in_my_armchair_and_it_seemed_like_a_good_idea" or
>> similar?
>> We've lost the information that the sign is actually NOT a 60 mph sign.
>>  Something like method 2 above would have avoided losing information
>> (although "GB:rural" is meaningless; if pushed, "GB:national" or some
>> variant would be better).
> Rather amusing, really. I noticed that this had happened overnight to a
> road near me, and messaged the user to draw his attention to this discussion
> - without twigging that the 'PeterIto' I was talking to was actually Peter
> Miller of ITO (I can be a bit slow on the uptake sometimes)!
> Having followed this discussion, I must say I'm rather surprised that Peter
> has done this without at least adding a source:maxspeed or maxspeed:type tag
> at the same time.
The main concern expressed by chilly and SomeoneElse was the extra work for
mappers. I therefore proposed the following to limit this extra work for
mappers (including me):

"Lets now consider default values for the maxspeed:type tag to cut down work
further. We could agree that the default value for maxspeed:type is numeric.
We could go further and say that the default value for maxspeed:type for a
single carriageway road with maxspeed=60 mph is 'GB:National' and also that
the default value for motorway and motorway_link with with maxspeed='70 mph'
is 'GB:motorway'. That way the extra tagging is only required in very few

There was no response to that proposal which I took to be broad agreement
and proceeded on that basis, however... given that it is still up in the air
lets discuss it properly.

What percentage of roads on which cars are allowed to travel at 60mph are
'GB:national' and what percentage are numeric? Someone has kindly provided a
Google Streetview image of one such '60 mph' sign which was on a 4 lane
single carriage road (ie one that may look to an average motorist as being
'dual carriageway'). I would suggest that 99% of 60mph limit roads in the
country are of the GB:national type and as such that this should be the
default value for maxspeed:type for 60mph roads.

As for 70mph speed limits, has anyone seen a numeric 70mph sign? I am not
aware of having done so but there could well be a few. However... the vast
majority of signs are of the type GB:dual-carriageway and GB:motorway and as
such again I suggest that this is a suitable default.

Any thoughts?


Peter Miller, alias PeterIto ;)

> Steve
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