[Talk-us] "highway" tags in the US

Karl Newman siliconfiend at gmail.com
Tue Mar 4 06:31:39 GMT 2008

On Tue, Mar 4, 2008 at 12:09 AM, Alex Mauer <hawke at hawkesnest.net> wrote:

> Karl Newman wrote:
> >
> > Agreed. The criteria listed on the Wiki page promote too many highways
> > to "motorways". It's too hard to distinguish between them; in dense
> > urban areas you could end up with a lot of "motorways". It seems to me
> > the "motorway" tag should be reserved for interstates, with some
> > exceptions for major US highways. You left out "tertiary" from your
> > descriptions. I would see "tertiary" as an important thoroughfare road
> > through a town--higher speeds and less traffic controls than
> > "unclassified". How about these guidelines, based on speed limits and
> > lanes:
> >
> >     * motorway: Interstate, 2+ travel lanes, ramp access only, speed
> >       limit 65 MPH+
> >     * trunk: US highway, 2+ travel lanes, ramp access only, speed limit
> >       60-70 MPH
> >     * primary: US highway, 1-2 travel lanes, or State highway, 2 travel
> >       lanes, speed limit 55-65 MPH, can have occasional
> >       stoplights/traffic controls
> >     * secondary: State highway, 1-2 travel lanes, or larger county
> >       highway, speed limit 45-55 MPH
> >     * tertiary: County highway, other unnumbered thoroughfare, speed
> >       limit 40-50 MPH
> >     * unclassified: urban commercial district or rural low-density
> >       housing, normally no direct driveway access to housing in urban or
> >       suburban areas, speed limit 30-40 MPH
> >     * missing_tag: It seems like there needs to be another
> >       classification for residential branch roads which are main roads
> >       through subdivisions but still have direct driveway access to
> >       housing.
> >     * residential: urban or suburban roads primarily for providing
> >       access to housing, speed limit 15-25 MPH
> >
> I agree, with the modification that trunk doesn't need to be ramp access
> only, and that county highways are secondary.

Okay, for trunk, how about *mainly* ramp access, with grade-level crossing
access to side roads permitted, but without traffic controls on the highway
where they meet?

Re: County roads as secondary, I was thinking mostly of speed limits as a
guideline for the classifications. There aren't a whole lot of numbered
county roads here in California, so I don't have much to judge them by.

> I've used tertiary for the missing_tag you describe, as this seems to be
> in line with the European tertiary roads.  (these comments are also on
> the wiki, I believe.

So you would place unclassified above tertiary? I haven't spent much time
looking at road classifications when I've been in Europe (I probably would
now since I've joined OSM), but that seems to go against the existing

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