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

Sun Dec 22 23:26:28 UTC 2013

Peter,

Yes, Magnificent Mile.  It's been a few years!

I don't have much argument with most of what you say.  I was reacting to
what I perceived as comments from some that "what the locals call it" should
get priority with regards shields.  It should be whatever the DOT has
designated the road as (see the mile markers when installed).

However there are many MAJOR roads with dual or more routes on them.  A
significant mid-west US example is I-80/I-90 from Elyria, OH to Gary, IN.
For OSM to display only one of those route numbers in its shields is not, in
my opinion, "user friendly" for map readers.  And as I noted, it appears
there is a problem with OSM and dual/multiple route tags in at least some
areas: no shields show for many miles where the dual routes exist.

Yes the MUTCD is a guide to what to hang on a sign post or overhead gantry
rather than a mapper's guide, but the use of multiple route signs on a
single pole tells you that the DOTs want us to know all the route numbers of
a given stretch of pavement.  The MapQuest Open layer of OSM does the same
and for me at least, this does not represent "shield clutter."

Kerry

From: Peter Davies [mailto:peter.davies at crc-corp.com] 
Sent: Sunday, December 22, 2013 2:53 PM
To: Kerry Irons
Cc: Tod Fitch; Martijn van Exel; OSM US Talk; Richard Welty; Eric Fischer
Subject: Re: [Talk-us] Prioritizing multi-banded route designators (multiple
overlaps) on ways: the "Principal route designator" concept

Kerry,

Your reference is to "The Magnificent Mile", a hyped up name for Michigan
Avenue, Chicago's main shopping street.  I happen to be sitting on a plane
to Chicago right now and the lady sitting next to me got your meaning
immediately. Check out http://www.openstreetmap.org/node/153654226

You say that "map users want to see all the route numbers on a given piece
of pavement, not just the ..." principal route.  Yet there are many
different types of map user, each with different needs and preferences.  I
had said "We need a way of capturing [the principal route designator] in OSM
for use in nav systems and info systems, as well as (perhaps) for ridding
simple maps of route shield clutter."

Note my "(perhaps)" and "simple maps".  I would never suggest that OSM
mappers want to be rid of what I risked calling "route shield clutter."  But
my job is to design map-based info systems for use by as many people as
possible, and this experience tells me that multiple route designators tend
to confuse the average user. My plea is that mappers ensure that the
principal route designation (which every numbered highway has, at least in
the eyes of police and DOTs) comes first in the way ref tag, so that simple
maps, nav systems and info systems can be created that "say it as briefly as
possible".  That way, you can have your "everything" maps and I can have my
relatively "simple" info systems for ordinary folks to use.

As a professional traffic engineer I know MUTCD moderately well.  The Feds
and AASHTO do a good job of imposing some degree of consistency on the 50
banana republics (sorry, the US states). ;)   But MUTCD is not written as a
mapping tool, nor as a design document for nav systems or traffic info
systems.  It's a useful guide to what we traffic engineers are supposed to
hang on poles and gantries. In OSM, the community decides what to map, and
my hope is to influence mappers to meet the diverse needs of many different
user groups.

Later today I'll be picking up my rental car from O'Hare and (over the
holiday) driving the Kennedy, the Eden, and the Dan Ryan, etc.  Like you,
I'm a relative stranger to Chicago, and I'd prefer to know them as I-90 and
I-94.  This is why we (if Castle Rock were the Illinois 511 contractor)
would reference a crash on the Dan Ryan as "On I-90 (Dan Ryan Expressway)
between Exit 53 (Canalport Avenue) and Exit 52 (Roosevelt Road) look out for
a crash ..."  We try to satisfy both the locals and the visitors.  Chicago's
radio stations have different goals. But if I didn't mention "Dan Ryan",
many of the locals would say "I-90? What is that?"

It happens that Chicago's freeways are not cluttered with "rubbish numbers"
(thank you Shawn Quinn; not my words).  Great job, I-DOT!   US 41 has stayed
on Lakeshore Drive, where it belongs.  

Kerry, our aims are not incompatible.  I'm happy to defend the way ref tags
too.  It had been suggested that we might only need relation ref tags. It is
true that there is much duplication.  My point is that way ref tags tell us
the priority order of the shields, and that we can get this no other way.

Peter

On Sun, Dec 22, 2013 at 7:19 AM, Kerry Irons <irons54vortex at gmail.com>
wrote:

Peter,

The "Miracle Mile" is probably an anachronistic reference, but I believe it
is a reference for a section of Chicago's Lake Shore Drive (also US 41).
Other towns have used this reference to their business district.  Note the
reference in Billy Joel's "It's Still Rock and Roll to Me."  For people like
myself who visit Chicago, "the Dan Ryan" and "the Eisenhower" don't mean
much, but I-90 and I-290 appear not only on maps but on exit signs,
wayfinding signs, and mile posts.  In the US, FWHA and the MUTCD have
standards for route numbering signs and typically ALL of the routes on a
given piece of pavement show up at key junctions (mile post signs will only
have the primary route, however that was determined).

My point here is that map users want to see all the route numbers on a given
piece of pavement, not just the primary route.  While OSM is very good about
capturing all the information in tags, if only one route number appears at
any given zoom level, those using the standard layer will not see the other
routes (they are visible in the MapQuest Open layer).  And in some cases,
multiple route number tags apparently cause the OSM Standard layer rendering
to simply not show any route number shields.  There is a section of I-75
near me that is also US-23.  In the OSM standard layer, neither of those
route numbers is visible at any zoom level for a 75 mile stretch of
interstate.  The same thing happens on US-41/M-28 west of Marquette, MI
until you get to z=13.  This is not a "user friendly" view for map users.

Kerry

From: Peter Davies [mailto:peter.davies at crc-corp.com] 
Sent: Saturday, December 21, 2013 11:30 PM
To: Kerry Irons
Cc: Tod Fitch; Martijn van Exel; OSM US Talk; Richard Welty; Eric Fischer
Subject: Re: [Talk-us] Prioritizing multi-banded route designators (multiple
overlaps) on ways: the "Principal route designator" concept

Kerry

I'm not sure that I follow your drift here, Kerry.  Can you elaborate about
the Miracle Mile?

Peter  :)

On Sat, Dec 21, 2013 at 6:45 PM, Kerry Irons <irons54vortex at gmail.com>
wrote:

All,

If you look at the guidance in the US from FHWA and the MUTCD, all route
numbers are to used in signage.  You never know who is using a given piece
of pavement by following which route number.  Just because the locals might
call it "the Miracle Mile" doesn't mean that is the appropriate choice for
shield priority.

Kerry

From: Peter Davies [mailto:peter.davies at crc-corp.com] 
Sent: Saturday, December 21, 2013 8:53 PM
To: Tod Fitch
Cc: Kerry Irons; Martijn van Exel; OSM US Talk; Richard Welty; Eric Fischer
Subject: Re: [Talk-us] Prioritizing multi-banded route designators (multiple
overlaps) on ways: the "Principal route designator" concept

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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