[Talk-us] followup on trunk in the US
Richard Welty
rwelty at averillpark.net
Fri Mar 26 13:46:54 GMT 2010
i have surveyed (to a degree) the wiki, and found a number of different
assertions about the use
of trunk in the US, and surprise of surprises, they're not terribly
consistent, and sometimes
outright contradictory (one asserts that trunks have speed limits less
than 50mph, another
asserts speed limits of 65mph+). extracts from the various definitions
are at the end of this
email, i don't claim it's comprehensive, but it is revealing that we as
a group are apparently
very confused about this stuff.
i am going to draft a set of questions based on these conflicting
definitions which i will
post here, with the aim of clarifying everyone's thinking. anyone who
has any proposed
questions for this survey should feel free to send them to me. the
intent is to ask pointed
questions and get everyone to actually think about this. i will include
links that point
to specific examples in OSM that bear consideration.
some example questions:
what does major intercity highway mean:
a major highway connecting two major cities
a major highway connecting two cities
a highway connecting two major cities
other?
what is a major city? (presumably population matters)
what defines major highway?
physical characteristics, e.g. speed limit, lanes, lane width
traffic volume
official/functional designation
US highway? part of the National Highway System (this includes
certain state routes)?
part of the STRAHNET system (designated roads for military use in
emergencies)?
richard
---------------
Definitions found in the Wiki (note that there are also definitions on
various
state pages, i didn't go get all of those):
Generic definition from
http://wiki.openstreetmap.org/wiki/Map_Features#Highway
Important roads that aren't motorways. Typically maintained by central,
not local government. Need not necessarily be a divided highway. In the
UK, all green signed A roads are, in OSM, classed as 'trunk'.
From http://wiki.openstreetmap.org/wiki/Trunk#International_equivalence
Divided highway without ramps.
Higher speeds (65+mph). This includes some US highways and some state
highways.
>From
http://wiki.openstreetmap.org/wiki/United_States_roads_tagging#Trunk_tag
(Interstate Highway section of page)
Trunk tag
NOTE: The definition below is not commonly used; see the talk page.
Many people use trunk to mean "expressway"-grade arterials with at-grade
intersections, major non-motorway intercity highways, or both.
Most controlled-access highways without adequate speed or travel lanes
or with obstructions should be designated highway=trunk. This
designation applies, for example, to the two-lane Interstate 93 in
northern New Hampshire. highway=trunk should apply to any segment,
travel on which typically implies or necessitates clearing the
obstruction. Any ramps onto or from a trunk highway get
highway=trunk_link, even if they otherwise qualify for
highway=motorway_link. Ramps leading into or from weigh stations,
inspection booths, welcome centers, rest areas, and similar diversions
accessible only from a trunk or motorway highway also carry
highway=trunk_link.
Trunk highways include controlled-access highways that lie within
military bases; contain draw bridges, toll booths, or other obstructions;
have a speed limit less than 50 miles per hour; or have only one lane in
each direction, whether divided or otherwise (sometimes called a
"super-two" freeway). The designations highway=trunk and
highway=trunk_link apply to all toll roads.
From
http://wiki.openstreetmap.org/wiki/United_States_roads_tagging#Motorway_and_Trunk_tags
(United States Highway section of page)
Motorway and Trunk tags
If any segment of a U.S. highway or any other road merits
highway=motorway or highway=trunk according to the criteria
heretofore described, it should be so designated.
From the talk side of US tagging (note that there is extensive
discussion which
i have not copied into this document)
http://wiki.openstreetmap.org/wiki/Talk:United_States_roads_tagging#Trunk
Trunk
Unless part of the "Interstate system"
* An Arterial Divided highway that is partially but not entirely
grade separated.
From http://wiki.openstreetmap.org/wiki/Roads#USA
US Highways should be tagged with highway=primary. State Highways and
County Highways should be tagged with highway=secondary. Any of these
which is a divided highway with high speeds (65mph+) and intersections
with other roads, and legal for bicycles and motorbikes to use, should be
tagged with highway=trunk.
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