[Talk-us] Prima Facie Speed Limits

Tod Fitch tod at fitchdesign.com
Wed Sep 10 18:15:23 UTC 2014

On Sep 10, 2014, at 10:49 AM, Richard Welty wrote:

> actually one of the most powerful motivators behind
> the widespread adaption of the MUTCD is liability.
> if states and municipalities show they are operating
> in accordance with the MUTCD then they can avoid
> a world of hurt in court. it's why the recent addition
> of a number of bicycle facilities to the MUTCD is a
> big deal, as it makes them suddenly ok for many
> jurisdictions where they weren't before.
> richard

Back to topic: What is the feeling of those on this list about the relative merits of marking each way with "maxspeed=*" and "source:maxspeed=US:ST:highwayclass" (or some equivalent) versus tagging the administrative area(s) with the prima facie speed limits for each class?

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.


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