I’ve got a wide urban primary road that has central hatching along its length to separate opposing traffic flows, reinforced by traffic islands at intervals. At the moment the road is plotted as separate carriageways although there is no physical barrier between the opposing traffic lanes. Would this be a correct representation, or should I turn it into a single primary? I note that traffic islands are generally ignored in OSM otherwise the single primary would have to split into two to signify their existence.
Unless there’s a physical separation it’s not a dual carriageway (there’s only a single carriageway - albeit strategically divided)
A dual carriageway has to have a “physical” barrier between the two opposing directions, even if it is just a patch of grass.
One way is to look for the “end of dual carriageway” and associated “two-way traffic” signs where that putative DC becomes a “normal” two-way road. They seem to put these everywhere, even on DCs that are only a few meters long.
Richard [in SG2]
The national speed limit along your road would be 60 because it isn’t actually two separate carriageways like the others pointed out. Whereas of course if it were a dual carriageway the speed limit would be 70. Even if there is more than one lane in either direction (as there is on a road near me) it is not necessarily a dual carriageway unless there are two separate pieces of tarmac.