I've created a page for Key:dual_carriageway based on existing usage in the database: https://wiki.openstreetmap.org/wiki/Key:dual_carriageway
On 2/20/20, Joseph Eisenberg <[email protected]> wrote: > I updated the Key:expressway page to have a global focus, rather than > being United-States-specific. > > But I noticed that the key:expressway is currently used in 2 different > ways. > > While all expressways are major roads designed for high-speed motor > vehicle traffic, they are not often "motorroad=yes", because most > States allow motorcycles and pedestrians on all roads that are not > motorways (and western States allow bicycles on rural motorways even). > > The defining characteristics are: > 1) The max speed and design speed are relatively high (usually 60 kmh > in urban areas or greater in rural areas) > 2) A) They have limited access to adjacent properties > OR > B) They have grade-separated interchanges with major junctions. > 3) They are dual carriageway (divided) highways > > While many "expressways" in the United States fit all of these > characteristics, many only fit 2)A) or 2)B) but not both. > > We already have "max_speed=", but it would be better if there were > more specific tags to describe these three properties: > > A) Limited access: there are no or very few service roads or driveways > B) Grade separation: there are no stop lights or stop signs (or > roundabouts) at junctions, instead the roads cross at different > levels, with link roads / ramps to connect them. > C) Dual carriagway: the two directions of travel are divided by a > barrier or median area. > > So initial ideas; > > A) a new tag "limited_access=yes/no" - or is there a better term in > British English for a road which doesn't have service roads like > driveways, or only very rare intersections with service roads? This > needs a proposal. > > B) Use the tag "grade_separated=yes/no" for roads that generally do > not have any at-grade intersections with stop lights, stop signs or > roundabouts or similar. Used only 97 times: > https://taginfo.openstreetmap.org/keys/grade_separated so should need > a new proposal. > > This property can be seen by looking at all crossing or intersecting > roads and interpreting layer= and bridge= and tunnel= tags, but that > is quite hard to get right, so having mappers add this tag would help > with quality control and make it much easier for database users. > > C): I noticed that the tags "dual_carriageway=yes/no" and > "type=dual_carriageway" have been used in a few limited areas. These > have been used several thousand times > (https://taginfo.openstreetmap.org/keys/grade_separated) but only in a > few places, so a new proposal is still a good idea. > > This property is also mapped by drawing two separate ways and adding > oneway=yes, but it is not easy for a computer algorithim to properly > interpret these geometries as "two parts of a single road" without a > tag like "dual_carriageway=yes", especially if there the name= and > ref= are not identical for each direction. > > - Joseph Eisenberg > _______________________________________________ Tagging mailing list [email protected] https://lists.openstreetmap.org/listinfo/tagging
