-Alan
Here is map...@att.net's old post:
A motorway is a four+ lane, limited access, grade separated freeway. These can include Interstates, US Highways, State Highways, County Highways or even Farm to Market Roads if they meet certain criteria. These criteria are limited access,the use entrance/exit ramps to access the freeway. Intersections with other roads are at grade seperated crossings or ramps. A grade separated crossing means one road goes over or under the other. (ie. over/underpass) When Motorways meet other motorways they generally use ramps that are classified as Motorway Link. These motorways usually connect to other cities or move the traffic around and through a city. Limited access ring roads usually fall in this feature class also.
A trunk is what a motorway becomes when it loses one of it's criteria. This usually occurs to US, State, County highways as they move outside the urban areas. Intersections with other roads can occur at grade and/or when ramps are no longer needed to access the road. Usually they remain 4+ lanes and may or may not be divided by a physical median.
A primary road can be a US, State, County Highway or other road that connects two cities or moves traffic from one part of the city to the other. These are the highways that become Main St when they go through a small rural town. They will have traffic signals when they reach more densely populated areas. These are the roads you jump on when the freeway has an accident and you don't want to sit and wait it out.
A secondary road moves traffic within a city. It would service only a certain area within a city.
A tertiary road connects the residential roads to the higher classes: motorway, trunk, primary or secondary.
I hope this clarifys things for some users. I know it's not going to please those who have already used other classification schemes.
thanks,
pete
From: David Lynch <djly...@gmail.com>
To: Talk-us <talk-us@openstreetmap.org>
Sent: Tuesday, February 3, 2009 8:49:26 AM
Subject: Re: [Talk-us] US Highway Classification (Was: directions of ways in MassGIS data)
What I've tended to do in my part of Texas is:
Motorway - two or more consecutive intersections with grade separation and no driveways, or any interstate (some very rural locations do have the occasional turn off directly from the main travel lanes)
Trunk - US highways without any other reason to classify them up or down and high speed divided roads with relatively few crossings and an occasional grade separation
Primary - State highways, US highways running near and parallel to a motorway, and wide, heavily-traveled urban/suburban streets
Secondary - Other state highways (farm-to-market roads, loops, spurs) and major city streets
Tertiary - Residential collector streets, some rural roads that are in good condition and connect to classified highways, and service roads running parallel to a motorway.
We need a detailed road classification chart on the US wiki page to straighten all of this out ! Maybe I'll find the time to get working on that one of these days... I think I'm also having trouble making the OSM road classification system do everything I want it to.
"the consensus is that the highway tag is for making a general description of the physical attributes of a highway. This gives the user of a highway more useful information than a legal classification." - Key: Highway (OSM Wiki)This is true for high zoom levels, but at low zoom levels this can be too much information. When I am looking at a map of an entire state, I want to see what the main routes are through that state, not every important road.
In Vermont some important 2 lane north/south routes are VT 100, VT 116, US 7, and VT 22A. Physically they are pretty similar, and so by OSM standards they should all be primary. In my opinion though, at low zoom levels US 7 should stand out from the others because it connects larger towns, has a higher legal designation, and it stands out on other maps.
I suppose this is really an issue for renderers, but we do need some sort of tagging for the renderers to use. Maybe once route relations become more prevalent renderers could emphasise different higher level route networks more, regardless of the physical highway tag. Any thoughts?
Zeke Farwell
Burlington, VTOn Mon, Feb 2, 2009 at 10:20 PM, Greg Troxel <g...@ir.bbn.com> wrote:
(replying to Zeke and Chris both)
I agree that if there is only 1 mile of motorway class road among
trunk-class road that tagging it motorway isn't useful.
The parts of Route 2 that I was thinking of tagging as motorway are
physically indistinguishable from an interstate, and at least 10 miles
long. I am not 100% clear that pedestrians/bicycles are banned, but I
think someone would call the police if either were on the road - I never
see them when driving on 2.`
As for the trunk designation, I find that a bit ocnfusing, but my
impression is that it is a road that is somewhat more than a regular US
highway physically, but not all the way to interstate. An example would
be a road with 2 lanes in each direction and jersey barriers, but
same-grade junctions with lights every few miles. Rt 2 is like this
between 128 and Tracey's corner (1st intersection west) and really all
the way to South Acton where it is motorway again until about 7 miles E
of Orange and then it's back to trunk (1 lane each way only, but with
exits). Further west it is just a primary road, but gradually being
made more like trunk.
I don't think being the only main road should qualify a way as trunk; it
seems being important is only enough to get a road to primary. But some
degree of limited access and being divided would be enough for trunk.
So I'd leave rt 2 as motorway/trunk mixed. I've driven rt 7 from
Bennington to Burlington, and it didn't in general feel like "almost an
interstate but not quite" - it felt on balance more like primary.
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David J. Lynch
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