[OSM-talk] Directional tagging

[Richard Bullock]

>
>>> b) 2+1 ways as we call them in Sweden, they are normal ways but have a
>>> small fence in the middle and 2 lanes on one side and 1 lane on the
>>> other side. They look like this:
>>> http://www.vv.se/filer/V?gprojekt/3-Falt.jpg
>>
>> I would say that these should be done the same way as motorways, with 2
>> parallel one way roads. The appropriate number of lanes can be added for
>> each direction.
>
> I understand that I can map them as two roads, but physically they are
> one road. So I'm thinking, why map them as two roads, when they are one.
> Motorways are different, they consist of two separated pieces of way.
> They have ramps and acceleration fields.
>

Where there is a physical barrier, splitting a road in two, tag as two 
separate ways, with a oneway tag. Where a physical barrier splits a road in 
two, this is a dual carriageway, regardless of how many lanes each 
carriageway has.

It doesn't matter if a dual carriageway has at-grade junctions (i.e. just 
gaps in the barrier or side-turnings), or motorway-style slip-roads and 
bridges - they are still both dual carriageways and must be tagged with two 
ways.