> in the UK some main A roads have single lane passing places and 10 > MPH speed limits while others are much higher quality than most motorways.
Are these not edge cases? Any general case model of classification will fail at the edge cases. No classification system will map cleanly onto the real world, where there are always extremes. The current model is simple, and allows for extra tags to describe a road that differs from what the highway= tag might lead one to expect. (primary road with low bridges or narrow lanes, secondary road with dual carriageway). With our current model, we can reasonably assume for any country that a road tagged highway=motorway is of higher quality than trunk > primary > secondary etc. We can make assumptions for each different country or even region that a given tag will specify a higher or lower quality than in another country i.e. you don't go from Northern France to Iceland expecting highway=primary roads to be of the same quality. But the principle that one highway type is better than another, *in* *general*, is true everywhere. In the UK, in general, the administrative classifications Motorway > green-signed A-road > white-signed A-road > B road > unclassified road - so these reasonably map to motorway, trunk, primary etc. The current model is simple, and *generally* does not surprise the user. The guiding principles of OSM. - Dan _______________________________________________ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/cgi-bin/mailman/listinfo/talk
