[Talk-us] Prima Facie Speed Limits

Richard Welty rwelty at averillpark.net
Wed Sep 10 18:29:41 UTC 2014

On 9/10/14 2:15 PM, Tod Fitch wrote:
> The more I think about it, tagging each way is a bit like "(incorrect) tagging for the router", basically creating a maintenance headache and cluttering the OSM database with stuff the current router and navigation guidance can use without being changed.
> But the rule is really for a whole jurisdiction and could be covered with a handful of tags, one for each highway class on the area or relation that describes the administrative area. That would allow for cases like Burlington, Vermont having prima facie limits even if Vermont doesn't (as was mentioned earlier in this thread). And it would allow easy updates if/when that administrative unit changes its laws, only a handful of tags all on one object versus changing potentially thousands of highway objects.
the tradeoff is added complexity for the data consumers
who  now have to process the boundary to determine maxspeed.

secondarily, we still need to tag the ways in some manner
(e.g. maxspeed=admin_default or something) so that it's
clear that someone actually was paying attention, because
otherwise (as i think Martin pointed out) the absence of the
tag could mean two different things.


rwelty at averillpark.net
 Averill Park Networking - GIS & IT Consulting
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