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<p>Thanks Kevin, you've really got the magic touch when it comes
extracting data from NY State. <br>
<br>
My offhand impression is that this map has a lot red. That
includes both things I feel are oversold (eg NY-23 east of NY-8,
currently tagged as secondary) and things I feel are undersold
(the NYC motorways... hard to make out exactly what's going on in
there, but there's hardly any blue.)<br>
<br>
I don't know the west end of state all that well, or northern
reaches, so I can't speak to that. But this certainly passes the
Ithaca-Rochester test. And I do feel there's some value to
employing the state's knowledge/opinions in this process.<br>
<br>
I fear we will, as you describe, end up with 50 to 56 different
wiki pages of highway tagging guidelines. So be it...<br>
<br>
Jason<br>
</p>
<div class="moz-cite-prefix">On 5/24/2021 4:20 PM, Kevin Kenny
wrote:<br>
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<div>I think it makes sense for the OSM highway class to have
rules at the level of individual states in the US, just as it
has rules at the level of nations in the EU. Except for the
Interstates, the US really has no national highway
classification system. US highways are actually nowadays
numbered by agreement among the states they serve, and the
FHWA functional classification is intended to prioritize
Federal aid for highway funding. Virtually all road
designation, construction and maintenance is carried out by
the states.<br>
</div>
<div><br>
</div>
<div>New York's GIS appears to have classifications that make a
modicum of sense. There's an Arterial Classification Code that
attempts to document that-which-is (rather than allocate
funding), for the express purpose of routing preference and
decluttering at low zoom levels. Its top couple of levels of
classification appear to be a decent match to 'motorway' and
'trunk'.<br>
</div>
<div><br>
</div>
<div>Note that this is distinct from the Federal functional
class, and the NY GIS system tabulates both. Federal
functional class is "what the road ought to be, and we'll use
that to allocate funds for improvements', whie arterial class
is "how the road actually is used - in terms of
appropriateness for routing and zoom level"</div>
<div><br>
</div>
<div>At the most significant levels, the chief points that are
likely to be controversial: </div>
<div><br>
</div>
<div>There are a few data entry gaffes. Most of these are
obvious, such as the fishing access service way <a
href="https://www.openstreetmap.org/way/20084827"
moz-do-not-send="true">https://www.openstreetmap.org/way/20084827</a>
being classed as 'minor arterial', probably because it was
inadvertently selected along with NY 23A.</div>
<div><br>
</div>
<div>There are short motorway segments like NY 85 from I-90 to
the first roundabout that are merely class 3. (Then again,
that segment is 'motorway' only by the 'three consecutive
interchanges without a level crossing' rule. It has four.</div>
<div><br>
</div>
<div>Some suburban freeways, and nearly all the parkways, are
class 2 rather than class 1. This list has seen arguments in
the past about roads like these, with some people contending
quite passionately that 'motorway' is inappropriate for a road
with `hgv=no`, or for a suburban freeway that does not carry
significant interurban traffic. The chief cause for the
disagreements appears to be that for the larger cities,
including the suburban freeway network clutters the map
unreadably at low zoom levels. Do we need an auxiliary tag to
identify 'suburban freeway?' (Most three-digit Interstates,
some NY parkways, NY 27 in Suffolk County, NY 33 and 198 in
Erie County, and so on)? It might help allay a lot of the
arguments. I'd still tag a road `highway=motorway` if it's
built almost to Interstate standards (both cross traffic and
opposing traffic fully grade-separated with all entry and exit
via ramps).</div>
<div><br>
</div>
<div>The class-2 roads often end short of urban centers. For
instance, the one-way pair that carries NY 13 through the
center of Ithaca is class 3. This is understandable from the
routing perspective; for instance, it encourages drivers to
bypass Manhattan unless their trip starts or ends there.
There is also a glitch or two - as with any data set. In the
Ithaca example, one block of West State Street between the
one-way pair is inexplicably marked as class 2. I suspect
this, and the downgrading of NY 13 south of town where it
splits very briefly into a one-way pair at the NY34/96
junction, are simple data entry errors. I think that all of
these issues could be resolved with a topology check: if a
trunk's classification dead-ends within a couple of miles,
say, of another trunk in the same route relation, or contains
routing islands, flag that bit for manual patchwork.</div>
<div><br>
</div>
<div>On the other hand, it might make sense for a trunk to end a
little bit short of a city center if it carries significant
traffic into and out of that city, but is unlikely to be a
significant conduit for intercity traffic not visiting that
city. I-95 across the extreme northern end is just about the
only case in Manhattan where a freeway or trunk road carries
traffic for which New York City is not a port of call.</div>
<div><br>
</div>
<div>The odd quad-carriageway Queens Boulevard / NY 25 is merely
a class-3. It makes sense, I suppose, given that the ten or
twelve lanes really just barely carry the local traffic.</div>
<div><br>
</div>
<div>Following the New York State classifications for New York
roads, except as necessary to patch topological
inconsistencies, would deflate most arguments that the
classification, at least here, is inherently subjective - it's
at least the subjective judgment of the arm of the government
that's responsible for the upkeep of the highways.</div>
<div><br>
</div>
<div>The result looks decently connected if a bit sparse. What
do others think here? <a
href="http://kbk.is-a-geek.net/attachments/20210524/NY-class-1-2.png"
moz-do-not-send="true">http://kbk.is-a-geek.net/attachments/20210524/NY-class-1-2.png</a>
- blue is class 1 (essentially all `motorway` except for the
missing part of NY 17), red is class 2 (some of these are also
motorways, but could disappear at low zoom; the rest are the
trunks).</div>
<div><br>
</div>
<div>-----------------------------------------</div>
<div><br>
</div>
<div>(Supplementary details follow.)</div>
<div><br>
</div>
<div>From the metadata: (<a
href="http://gis.ny.gov/gisdata/supportfiles/Streets-Data-Dictionary.pdf"
target="_blank" moz-do-not-send="true">http://gis.ny.gov/gisdata/supportfiles/Streets-Data-Dictionary.pdf</a>):</div>
<div><br>
</div>
<div>> ACC: Arterial Classification Codes (ACCs) categorize
roads according to the level of travel mobility that<br>
> they provide in the road network. Mobility refers to the
volume of traffic that a stretch of road carries and the<br>
> length of trip that it serves. Roads at the highest level
of mobility serve the greatest number of trips and the<br>
> longest trips. Conversely, high-mobility roads provide
the lowest level of access to property. Low-level, local<br>
> roads serve that function.</div>
<div><br>
> This system uses a six-level system, with 6 as the lowest
level, 1 as the highest. A list of the Arterial<br>
> Classification Codes is in Table 2 below. Ascending
through the levels, each step represents an increase in<br>
> relative importance to routing – an increase in the
number and length of routes using the road. In general, a<br>
> step up also represents an increase in traffic-volume
capacity of the road, an increase in vehicle operating<br>
> speed, and a decrease in travel time. (This system is
similar to, but not tied to, the Federal Highway> <br>
> Administration’s Highway Functional Classification
System.)</div>
<div><br>
> The primary use of ACCs is in automated routing. Using
ACCs, a routing program calculates the maximum use<br>
> of the highest-level roads that are appropriate to the
scale of the desired trip. This is analogous to the route<br>
> planning of a typical driver, who uses the highest-speed
road available, within the geographic range<br>
> established by the origin and destination points. The
hierarchical nature of the ACC levels allows for more<br>
> efficient access to relevant routing networks for a given
route, and in turn reduces system requirements.</div>
<div>> The implementation of ACC also supports its usage for
map rendering. Using ACC as a cartographic tool<br>
> allows for a variety of enhancements including:<br>
> 1. The display of “important” roads.<br>
> 2. Reduction of line density and visual clutter based
on scale of map<br>
> 3. "Visual Routing" on paper maps (the end user
chooses a route based on ACC display)<br>
> 4. Effective zoom layering in digital applications<br>
</div>
<div><br>
</div>
<div>The table for 'arterial classification' is complicated and
appears on page 15 in the document linked above.</div>
<div><br>
</div>
<div>Kevin's summary of ACC's as they appear actually to be
used:</div>
<div><br>
</div>
<div>1. Most major through-roads for interstate commerce.
(Two-digit Interstates, plus a handful of similar roads such
as NY 17, the Berkshire Spur, I-495 east of the Cross Island
Parkway interchange, I-390, I-684 and the Hutchinson River
Parkway. All of the ones I observe in New York are properly
`highway=motorway`, with the sole exception of the short
non-motorway segment of NY 17 between Deposit and Hancock,
which is also what keeps NY 17 from being designate I-86 (much
of it is signed 'Future I-86'.</div>
<div><br>
</div>
<div>2. Many three-digit Interstates. Most state parkways. Most
US Highways (4, 44, 20, 9, 9W, 209, etc.) outside the cities.
NY 7 between Bennington and Troy, between Latham and
Niskayuna. NY 25 and NY 27 on Long Island. Also, many lesser
roads in the hinterland that carry great local economic
significance. In particular, for Russ Nelson's concern that
the classification would leave communities north of the
Adirondack Park isolated, US 11 would be included, as would NY
56 from US 11 to Massena, NY 37 from Massena to the Cornwall
border crossing, and NY 812 from NY 12 to the Ogdensburg
border crossing. Addressing Jmapb's concern, Ithaca is served
by a single trunk (NY 13) that joins it to the two nearest
motorways (NY17 and the Thruway), and then a whole radiating
star of class-3 roads. In Manhattan, it's the ring road (West
Street, Henry Hudson Parkway, FDR Drive) surrounding the
island, plus connections to the tunnels (Lincoln, Holland,
Brooklyn-Battery/Hugh Carey, Queens-Midtown) and certain
bridges (George Washington, Manhattan, Williamsburg, and
Triborough/R.F. Kennedy), including the crosstown arterials of
34th Street and Delancey and Canal Streets, and roughly
mile-long sections of 8th, 9th and 10th Avenues and 14th and
23rd Streets needed to get vehicles between the tunnel
entrances and the ring-road interchanges. A handful of surface
streets in the immediate vicinity of the other tunnels are
included. In the outer boroughs, almost all the freeways are
class 2. (The class 1's are the two-digit interstates, the
Hutchinson River Parkway and the Throgs Neck Bridge.)</div>
<div>I-495 east of the city line and the segment of the Cross
Island Parkway that connects it to the Throgs Neck Bridge are
the only class 1's on Long Island. The class 2's appear to
include all motorways, plus NY 25 Truck (not NY 25 where the
truck route parallels it), NY 24 and NY 27 at the East End.</div>
<div><br>
</div>
<div>3. Intra-state and intra-metropolitan primary roads. These
are something of a mixed bag. Note that they do NOT include
all of the numbered state highways, and this is appropriate
(some are really local connector roads or don't really serve
any fair-sized towns. These look to be a good fit for
`highway=primary`.</div>
<div><br>
</div>
<div>4. 'Minor arterial' These would be a good match to
`highway=secondary` except that physical characteristics enter
into the state's classification too much, creating routing
islands at this level. In any case,
primary/secondary/tertiary is not the immediate question. I
think `minor arterial` could be a really good starting point,
though, with some small amount of manual patchwork required.</div>
<div><br>
</div>
<div>5. Pretty much everything else in the public road network:
tertiary and unclassified highways, residential streets, urban
collector roads that don't rate 'secondary highway', and so
on. The local streets.</div>
<div><br>
</div>
<div>6. Almost all class 6 roads are the access roads for
apartment complexes, commercial establishments and industrial
facilities, and `highway=service` looks to be appropriate for
most of them. (For the smallest ones, the usual arguments
among 'service', 'track', 'residential' and 'unclasified' come
up. I'm not going there in this message.)</div>
<div><br>
</div>
<div>A rough idea that I think could work for New York:</div>
<div><br>
</div>
<div>Class 1 roads - All 'motorway', except that the anomalous
section of NY 17 would have to be downgraded.</div>
<div><br>
</div>
<div>Class 2 roads - These should be 'motorway' if they are
built to near-Interstate standard, 'trunk' otherwise. They
need topology checks.</div>
<div><br>
</div>
<div>Class 3 roads - These are all at least 'primary'. Topology
might require upgrading some of the rest of the network to
avoid routing islands at the 'primary' class.</div>
<div><br>
</div>
<div>Class 4 roads - These should all probably be at least
'secondary' - including some only-partially-paved roads like
Ulster County Route 47, where they've pretty much abandoned
the attempt to preserve a hard surface through the mountain
pass, but which provides the only access to the Oliverea
valley. There are a lot of routing islands to patch.</div>
<div><br>
</div>
<div>Class 5 roads - I'd argue that any numbered county highway
(whether or not the county signs its numbered highways, so
Westchester and Nassau Counties count!), any state touring
route, or any state reference route (These last are all
unsigned, with four exceptions) rates at least 'tertiary'.
Otherwise, we're down at the 'local road' level, and we know
what a morass 'unclassified', 'residential', 'service' and
'track' have become.</div>
<div><br>
</div>
<div>Class 6 roads - Usually 'service', but again we have the
morass of 'lowest-level roads' to deal with.</div>
<br>
<div class="gmail_quote">
<div dir="ltr" class="gmail_attr"><br>
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<div><br>
</div>
-- <br>
<div dir="ltr">73 de ke9tv/2, Kevin</div>
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