I have been doing a lot of mapping of Thailand recently, and the country has many roads that are separated by an impassable median. I am assuming that any road where the median is physically impassable (such as having armco/concrete barrier, hedges, or even grassed areas) should be drawn as two parallel ways (with one way tags usually). Conversley, any road where the divide can be physically (even if illegally) crossed, such as a white line, even if double & continuous, then it is to be drawn as a single way. Does that fit with OSM convention ? Russ asked 17 Apr '11, 20:07  Russ McD edited 27 Feb '12, 20:54  Kozuch |
3 Answers:
Yes, it does. answered 17 Apr '11, 20:13  Richard ♦ |
In Openstreetmap only a physical barrier (or a patch of grass) between the lanes makes it necessary to map it as two ways. So yes that's the convention in Openstretmap. answered 27 Feb '12, 14:32  emj edited 27 Feb '12, 14:46 |
Yes. There's a section on this old wiki page: Editing Standards and Conventions#Divided highways And here's an example of an awkward road in London which has a barrier in the middle down some of its length. answered 27 Feb '12, 15:42  Harry Wood |
Don't forget to add all kinds of turn restrictions though: on a four way crossing you will need four no left turns and two no straights. This requires lots of cutting ways, too. Cumbersome...