[OSM-talk] What's the policy on unsurveyed roads from imagery?

David James david at djames.org.uk
Sun Dec 27 13:52:38 GMT 2009


> 2009/12/27 John Smith <deltafoxtrot256 at gmail.com>:
>> In Australia there is this legacy speed limit sign for people with
>> racing licenses that they can drive any speed they wish, everyone else
>> is limited to 100, how exactly do you map that? (and I saw one such
>> sign only the day before yesterday).
>>
>
> Umm, actually that one's a bit of an urban myth.  The sign (and it's a
> UN standard sign, not just Australian) means "end of local speed
> limits, back to State/Country default speed limit."  The racing
> licence thing comes from very old rule in NSW where they didn't
> enforce the limit (for anybody) as long as you were not driving at
> "excessive or dangerous" speeds, and no longer applies.  Somebody once
> used the "I'm a racing driver, it's not excessive for me" excuse and
> got off.
>
> As long as you know the state default speed limit, this is easy to
> tag.  It is exactly the same as a sign with that limit.

Except that there is the possibility that the default limit might change
in the future. In that case if default limit signs had been tagged with
the limit as it was when they were tagged, they'd now all need to be
changed.

In the UK that sign means "national speed limit applies"; the national
speed limit is different for single carriageways, dual carriageways, and
motorways (though I think all motorways are explicitly signed with the
relevant speed limit). The national speed limit has changed in the past.

-- 
David James







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