[Talk-us] US highway classification

[Dale Puch]

I have only skimmed these messages, so forgive me if it was already brought
up.
There are two criteria I do not think were brought up.  Length of a road, ie
is it important for the city, county, state, or country.  This needs to be
balanced with the width, and other features of the road like intersections
ect.
The other is relative importance of the road.  I know this is subjective,
but for places without many roads, even a dirt road might be a main
connector between points.

In the end this is a map, and it needs to inform of the best roads to get
from place to place.  This will depend on the map scale and distance
traveled.  Longer roads, especially ones with good throughput should
generally be the higher class roads.

Dale

On Tue, May 31, 2011 at 10:37 AM, Kristian Zoerhoff <
kristian.zoerhoff at gmail.com> wrote:

> I hate it when I forget to hit Reply-All....
>
> On Tue, May 31, 2011 at 8:54 AM, Greg Troxel <gdt at ir.bbn.com> wrote:
> >
> > Kristian Zoerhoff <kristian.zoerhoff at gmail.com> writes:
> >
> >> On Mon, May 30, 2011 at 10:41 PM, Toby Murray <toby.murray at gmail.com>
> wrote:
> >>> On Sun, May 29, 2011 at 4:05 PM, Nathan Mills <nathan at nwacg.net>
> wrote:
> >>>> On Sun, 29 May 2011 12:09:30 -0700, Paul Johnson wrote:
> >>>>
> >>>>> I'm thinking the differences between motorways and trunks are minor.
> >>>>> Trunks may have intersections, motorways don't.
> >>>>
> >>>> That's the simple way to state my opinion. It also seemed to be the
> thrust
> >>>> of most of the discussion on the talk page of the wiki page referenced
> >>>> previously as closest to consensus (the page itself just references
> the
> >>>> existence of the two camps and leaves it at that).
> >>>>
> >>>> In short, my position is simply that an end user expects a trunk road
> to be
> >>>> identifiably different than primary or secondary. That's how it's done
> on
> >>>> other maps, so I don't see why that's such a bad thing here.
> >>>
> >>> I agree with this as well. And I too thought this was a pretty widely
> >>> accepted convention.
> >>
> >> That's one accepted convention, to be sure, but it sometimes ignores
> >> the realities of where traffic goes.
> >>
> >> To give an example: <http://osm.org/go/ZUdwt69>
> >>
> >> IL 72 (the secondary at the top of the map) is a 4- to 6-lane at-grade
> >> expressway; wide median, lights only every mile or so, speed limit up
> >> to 55 mph. It carries a fair amount of traffic, but because it
> >> parallels I 90 (a toll road here), it really only peaks at rush hour,
> >> when the toll road is near capacity..
> >>
> >> US 20 (the trunk at the map bottom), is a 4-lane, non-divided road,
> >> but it carries far more traffic than 72, as it connects the two
> >> motorways at the map ends (the Elgin-O'Hare Expressway, and the Elgin
> >> Bypass, which were never connected). It's not particularly
> >> distinguishable from a lesser 4-lane road, aside from the absurd
> >> amount of traffic it carries. If we stuck purely to the above
> >> convention, 72 would be trunk, and 20 would be primary (at best).  But
> >
> > But what's wrong with that?  It sounds like IL 72 is a higher-class road
> > in terms of the physical road, and US 20 doesn't seem to have
> > almost-motorway features.   Just because a road that is properly
> > labeled primary is heavily used doesn't make it a higher class; you
> > certainly wouldn't label it a motorway based on traffic count.
>
> No, but motorways are such a special case of highway I really don't
> think we should use them as a basis of comparison. You're either a
> motorway, or you aren't.
>
> >> traffic flow cares more about where the road goes, not what it looks
> >> like.
> >
> > Sure, and routers can use that.
> >
> >
> > Probably we need to completely decouple
> >
> >  nominal importance in the hierarchy of road types
> >  physical characteristics
> >  importance to the people who use it
>
> Haven't we already? Physical characteristics have tags (surface,
> lanes, maxspeed). It's the hierarchy that seems to be the sticking
> point, and that's exactly what I thought "classification" was.
>
> --
> Kristian Zoerhoff
> kristian.zoerhoff at gmail.com
>
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