[OSM-talk] Changed highway=*_link meaning?!

[Lester Caine]

Andy Allan wrote:
> They can be used by routers to give more accurate descriptions - e.g.
> since we don't (yet) indicate junction priorities, it can be helpful
> if you are on a *_link and going onto a * to announce it as "join the
> main carriageway". If it was e.g. just highway=trunk for both, the
> router wouldn't know you were on a slip road. Same for when you are
> approaching an exit, it's a nice hint to the router that you aren't
> following the main carriageway.

And if you don't have the *_link, then there needs to be a replacement tag to 
provide that information! Although it should be possible to identify links 
between different road types, some will still be 'motorway' while others are 
slip roads and so join or leave. It is more difficult to decided what is going 
on where the slip roads are between one motorway and another, or motorway and a 
major trunk road. THESE needs to be specifically identified, and we had this 
discussion some years ago when the *_link tags were added!

-- 
Lester Caine - G8HFL
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