[Talk-GB] Maxspeed tagging for the UK

Ed Avis eda at waniasset.com
Tue Apr 12 15:16:24 BST 2011

Peter Miller <peter.miller at ...> writes:

>Are people happy with:
>GB:motorway (which implies 70 mph at present and possibly 80 mph in the future)
>GB:dual_carriageway (which implies 70 mph at present)
>GB:single_carriageway (which implies 60 mph at present)

I think this is a sensible scheme and can go either into 'maxspeed' (in which
case client applications will need a lookup table of what GB:motorway means)
or else into 'maxspeed:sign' (in which case the 'maxspeed' tag contains the
literal mph value, and will need automated retagging in case the national limit

However, one flaw is that the speed limit sign is not for 'dual carriageway
limit applies' but rather 'national speed limit applies'.  So we still would not
be tagging exactly what appears on the sign, but adding some additional
interpretation.  I think that is fair enough, but those who hold to a strict
on-the-ground principle may disagree.

(I don't currently map speed limits unless they are very low, like 5mph, so my
view should not carry as much weight as that of mappers who actively maintain
the highway network, or those who use the speed limit data.)

Ed Avis <eda at waniasset.com>

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