I encountered both cases and can't seem to find the rule. Some 2 way-streets that are separated by a continuous white line are represented bu only one segment and sometimes by 2 segments. |
Generally - for streets - we map 2 parallel ways when there is some kind of physical barrier, and one way only when the divider is simply a line. The boundary is blurry though. I suggest that you choose which form of mapping works best for you and apply that, without attempting to change the work of others to fit your personal style. |
In most cases, a barrier will help determine whether to use 1 or 2 ways. Another test is whether navigation directions for a left turn from a driveway would result in a misleading route such as "turn right, then make a U turn at the next intersection". |
Can you give examples of both? It'd be easier to know what you mean by "2 segments" then.
@SomeoneElse: See this: http://www.openstreetmap.org/way/294623880 - one way for a two-lane, two-way street. The westernmost node is connected to two ways, 1 lane each, 1 direction each - yet there is no significant change in actual, on-the-ground street properties. http://www.openstreetmap.org/way/25920361 http://www.openstreetmap.org/way/4064054
That way's a good example of why I was asking - there are two parallel segments to the west, and at the east end http://www.openstreetmap.org/node/2982164520 splits 2 sections of Bucharova with different tags (in this case a different number of lanes).
The east end is different for lane tags - I'm not disputing that. But the west part could be IMHO mapped as a single, two-lane way, with the same meaning as the current two one-ways have (couldn't be merged with the longer one, as there are different relations on both).