I am based in the UK but have also done some remote editing of US data. The UK is of course the basis of the classification terminology used by OSM for historical reasons.
The key thing from my side is to ensure that the order is retained, ie a motorway should have more capacity and probably flow faster than a trunk etc etc. This is essential to allow routing engines to use the best road available. The proposed scheme does that. The initial coding of interstates as 'secondary' did not. There is always some subjectivity involved, but it will be good of the approach is consistent across the country. I agree that both motorway and trunk roads should generally be free of traffic lights etc. The difference in the UK between the motorway and a trunk road is legal, the speed limit is different and motorways always have a higher spec, always have ramps, never have roundabouts. I was not able to determine when I should use Trunk and motorway in the USA and tended to use motorway. Primary roads seem to me to be the core tag for major arteries in towns (or countryside) where there were multiple lanes but also have side roads, traffic signals etc. Secondary and tertiary roads are really very pretty minor in the UK. In urban areas they are the roads that would feed multiple residential roads and residential roads would tend to not be through-routes. Here is an area I spent some time on in Foster City and the classification of roads seems to have stabilized over the past month or so. Motorway for everything with ramps, Primary for the big road with traffic signals and then secondary and tertiary to make sense of local circulation in residential areas. I didn't see any place to use highway=trunk http://openstreetmap.org/?lat=37.5413&lon=-122.2661&zoom=13&layers=0B00FTF I seem to remember that it was me who made Skyline Bvrd a trunk road here (http://openstreetmap.org/?lat=37.7233&lon=-122.4942&zoom=14&layers=0B00FTF ) . It seems to have stuck, but I am not sure if others would agree with that. It does seem odd for a trunk to turn straight into a secondary when it takes a lot of the same traffic towards the north although if most of the traffic heads up Great Hwy then that might be appropriate. Here is a map I have just done showing the use of highway=trunk in the USA which is interesting and shows the very uneven adoption of trunk across the country. There are pockets where it is being used a lot and areas where there is no use of it. http://www.flickr.com/photos/itoworld/3113029093/ Out of curiosity I have also added images for the other main road classifications: motorway: http://www.flickr.com/photos/itoworld/3113880022/in/pool-itomedia primary: http://www.flickr.com/photos/itoworld/3113885464/in/pool-itomedia secondary: http://www.flickr.com/photos/itoworld/3113063009/in/pool-itomedia I think the main message from these images is that the motorway tag is being used reasonably consistently across the country, the trunk road tag is only being used in pockets. Primary is used a lot especially in the east where it seems to form a complete network which is doesn't in the west. The use of secondary seems to be somewhat dependent on some arbitrary boundaries; are these state boundaries? I hope that is useful. Btw, do subscribe to our Flickr itomedia group (http://www.flickr.com/groups/itomedia/pool/ ). We release images on a regular basis and are happy to take requests for bigger areas. Do also use OSM Mapper ourselves to make your own images at the city level: http://www.itoworld.com/static/osmmapper Regards, Peter Miller ITO World Ltd www.itworld.com On 16 Dec 2008, at 17:01, Russ Nelson wrote: > map...@att.net writes: >> A motorway is a four+ lane, limited access, grade separated >> freeway. > > Like an Interstate. > >> A trunk is what a motorway becomes when it loses one of it's >> criteria. > > Like NY-17 used to be (haven't driven on it in twenty years, so maybe > the grade crossings have been eliminated), or like the Taconic State > Parkway. > >> A primary road > > As is US-11, particularly relative to Interstate I-81. > >> A secondary road moves traffic within a city. It would service only >> a certain area within a city. > > Mmmmmm, this is somewhat ambiguous. You could have a limited-access > highway which only moves traffic within a city; example I-2XX > highways. What are the criteria for secondary roads outside of > cities? For example, what is US-11B, or US-11C ? They are roads > equivalent in quality to US-11, however they are bypasses; are they > 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. > > IMHO (I may be wrong), but the solution to these quandries is: Use > More Tags. The more tags you use to accurately describe a road, the > less important becomes the "highway" tag. > > -- > --my blog is at http://blog.russnelson.com | Delegislation is a > slippery > Crynwr sells support for free software | PGPok | slope to prosperity. > 521 Pleasant Valley Rd. | +1 315-323-1241 | Fewer laws, more > freedom. > Potsdam, NY 13676-3213 | Sheepdog | (Not a GOP > supporter). > > _______________________________________________ > Talk-us mailing list > Talk-us@openstreetmap.org > http://lists.openstreetmap.org/listinfo/talk-us _______________________________________________ Talk-us mailing list Talk-us@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-us
