[Talk-us] Prioritizing multi-banded route designators (multiple overlaps) on ways: the "Principal route designator" concept

[Peter Davies]

Tod,

I found a common stretch of CA 108 and CA 120 between Oakdale and Yosemite
Junction in Tuolumne County.  I'm not sure if that's the double-banded
section you mention.

As Eric Fischer said, there are some ways that carry two approximately
equal routes, and my suggestion was that they would both still feature in
the way ref tags, in this case "CA 108;CA 120" (which is in fact what OSM
currently has for these ways).  I agree that there is no obvious precedence
order in this case other than "highest system, lowest number" (which is
again what OSM has at present).

My suggestion was (and is) that if we need to have multiple refs, because
two or more routes are about equal, the "way refs" be listed in shield
posting order, starting with the top or left-most shield.  Without going
there, we won't know if that is CA 108 or CA 120, or whether it varies.
 Since both are about equal it probably doesn't matter, because (as you
say) both should probably be mentioned.

My interest was more in what Shawn Quinn calls "rubbish numbers", such as
US and state route refs multi-banded on an interstate.  I think he argues
that we need them all.  I don't think that's in doubt, either.  But do we
need them all to be listed in every way ref, or would it be sufficient to
have them in the relation refs, with the first listed shield(s) emphasized
in the way refs?

I think the answer is already emerging.  Way ref tags with complete lists
of overlapping secondary route designators are here to stay.  Personally
I'm happy about this so long as the first signed route number(s), starting
from the top and/or left of the direction signs and route confirmation
signs, come first in the way ref lists (as they usually do in OSM already).
 So, I 465 should be listed before US 31, or IN 67, say, as it's given
greater precedence in the signing.

In other words, most people probably think that Interstate 465 is
Interstate 465, and not US 31 or IN 67.  So we should list it first (as we
almost always do).  Sound fair?

Peter


On Sat, Dec 21, 2013 at 4:37 PM, Tod Fitch <tod at fitchdesign.com> wrote:

> On Dec 21, 2013, at 2:35 PM, Peter Davies wrote:
>
> Kerry
>
> <snip>
>
> It's also perfectly fine if we want to keep all of the secondary
> designators in the ways' ref tags, as long as the most important one is
> presented first.  We can easily ignore the less important numbers.  But
> without a way ref (i.e., using only relation refs, as has been suggested)
> we have no way of knowing what is the most common route designator for that
> specific way.
>
> Peter
>
> There may be no "most common route designator". A semi-local example: If I
> am directing you east over Sonora Pass I'll tell you to go east on CA 108.
> If I direct you to Yosemite I'll tell you to go east on CA 120. But for a
> number of miles they are the same road with dual signage with no obvious
> method of tell which one is the most common designator.
>
> (You can probably tell what the road officially is by looking at the very
> cryptic and hard to read version of a mile/information posts that CalTrans
> uses but most motorists never notice them and if they do they are very
> difficult to read or decipher without stopping.)
>
> Some of your examples are in areas I am not familiar with. But in both the
> San Francisco Bay Area and Los Angeles there are named freeways. I notice
> that in the Bay Area the name is almost never used whereas in LA it seems
> both are used with the name being more common. In either case I'd expect
> the name key to specify the name and the ref to specify the route number.
> How you decide that a local would be more likely to use the name (LA) or
> the ref (SF) I haven't the fainted idea.
>
> Tod
>
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