[Tagging] maxspeed:type vs source:maxspeed // StreetComplete

Mark Wagner mark+osm at carnildo.com
Wed Sep 19 05:15:32 UTC 2018

On Tue, 18 Sep 2018 20:36:06 +0200
Tobias Zwick <osm at westnordost.de> wrote:

> From your anecdote, it seems, an implicit speed limit tagging scheme
> is even more important in the US than for example in the UK

In my part of the US, a meaningful implicit speed limit tagging scheme
is impossible, due to the three sets of laws regarding speed limits.

The first set is RCW 46.61.405, 46.61.410, 46.61.415, and 46.61.419,
which give various people the authority to set signed speed limits,
obedience to which is required by RCW 46.61.050.

The second is RCW 46.61.400(2), which establishes default speeds of
25 MPH on city streets, 50 MPH on county roads, and 60 MPH on state
highways.  This would seem rather comprehensive, except for:

The third law: RCW 46.61.400(1).  "No person shall drive a vehicle on a
highway at a speed greater than is reasonable and prudent under the
conditions and having regard to the actual and potential hazards then

As a highway engineer pointed out to me recently, most county roads,
especially unpaved ones, are designed around a speed limit of
"reasonable and prudent".  The 50 MPH limit established by RCW
46.61.400(2)(b) simply sets a firm upper boundary; it's quite possible
to get a speeding ticket at a lower speed.

Sure, you can put a number on any road.  But for most rural roads
without speed-limit signs, the number is unrelated to how fast you can
drive on that road.


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