[Talk-us] US highway classification

[Richard Welty]

On 5/27/11 12:00 PM, Alex Mauer wrote:
> On 05/27/2011 09:06 AM, Richard Welty wrote:
>> if you peruse the wiki, and make a reasonably through search
>> for definitions of trunk in the US, you will find an extensive
>> complex of contradictions and inconsistencies.
> Maybe someone should find all these and bring it up on the list so that
> a definition can be determined and the inconsistencies can be fixed?
>
> Just saying “the definition is inconsistent so I’ll just use my own
> interpretation” isn’t very constructive.
as it happens, i did this a while back. there may have been edits since
i collected this stuff, but i included the URLs where the text came from
for a reason.

Definitions found in the Wiki:

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.