[Tagging] Freeway exit tagging

Jack Burke burkejf3 at gmail.com
Thu Aug 25 21:15:16 UTC 2016

Freeway exit tagging

I am totally confused.

What is the proper method to use turn:lanes to tag freeway lanes
approaching an exit, where the exit branches directly from an edge lane
without being part of the freeway itself, but the freeway lanes are not
signed with an arrow, such as this one?

Through examples[1], the wiki shows that when the freeway lanes *are*
signed, then "through;slight_right" appears to be the correct value.  The
wiki examples also appear to indicate that "through" is *only* appropriate
when there is corresponding signage.  The wiki is also very clear what to
do when an edge lane is an exit-only lane ("slight_right"), and what to do
when a lane is signed for both through and right turn ("through;right").
So what's the right thing to use when there is no "through" indicator, yet
there is an upcoming branching exit?  By inference from what's contained in
the wiki, "none;slight_right" appears to be the appropriate value, but it
looks like a lot of people are disagreeing with that[2], even though it
appears to be the only logical conclusion.  Others think that
"through;slight_right" should be used because it's the reality on the
ground[2] despite the lack of paint/signs.

I'm bringing this up because I'm trying to get exits on I 75 in Georgia and
Florida tagged with destination and lane guidance (though only one
navigation app processes lane guidance AFAIK, but I hope that by adding the
data, others will take it up, too), and don't want to waste my time tagging
it incorrectly.  One helpful group trying to fix what they consider
incorrect lane counts & tags, turned a bunch of my continue-or-exit lanes
tagged with "none;slight_right" into exit-only lanes[3] with just
"slight_right".  I'm worried about switching to "through;slight_right"
because I don't want some *other* do-gooder coming along later and
similarly breaking lane guidance because there's no arrow on the ground or
on a sign.  Thus, I am now at a standstill because there doesn't appear to
be any correct tagging scheme for this incredibly common situation.

Note:  I am intentionally leaving the proposal for "transit:lanes" out of
this, both because it hasn't been voted on, as well as it doesn't appear to
cover this situation any better than turn:lanes does.



[1] http://wiki.openstreetmap.org/wiki/Key:turn

[2] https://lists.openstreetmap.org/pipermail/tagging/2016-June/029335.html

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