[Routing] [motorway_link] description of direction

[Jon Bright]

Hi Steffen,

Steffen Wickham wrote:
> 
> For example (in Germany): I'm starting at north Braunschweig and 
> entering a highway leading south. At the beginning of the motorway_link 
> leading to the motorway there is a sign with "Kassel, Salzgitter, Bad 
> Harzburg". Kassel is the next huge/famous junction, Salzgitter and Bad 
> Harzburg are the next city in south of Braunschweig.

The way Germany does this is quite Germany-specific - other countries' 
signing systems are at times quite different.  I'd think a better 
solution, which would make more countries happy, would be to be able to 
tag a given node for example as

signpost=Dortmund, Münster

Or

signpost:1=Dortmund, Münster
signpost:2=Dortmund, Münster
signpost:3=Wuppertal, Köln
signpost:4=Sprockhövel

For some complicated 4-lane thing.  (I'd suggest those lanes be counted 
from left to right, since that's the direction that most OSM users 
currently read in).

Doing this like this would also give you extra value: at the moment, 
stuff outputting routing directions doesn't know which lane to tell you 
to be in.  Obviously, the ideal solution would be to have more data in 
OSM telling you which lane is going to end up on which road.  But until 
such time, being able to look at which signpost you're going to see once 
the roads have split and then compare with the signpost tags above would 
be enough to be able to spit out a direction like "Stay in the 3rd lane 
from the left" or so.  Much better than my TomTom's current method of 
"Stay in the left lane", followed 10s later by "Stay in the right line", 
then "Stay in the right lane", then "Stay in the left lane", then "Join 
the motorway" - all this as you gradually work your way around a 
junction between two motorways.  It really does this, and it sounds insane.

Jon