[OSM-newbies] Joining two pieces of a way

[Per Lindström]

söndag 20 december 2009 18.41.59 skrev  Jeff Barlow:
> Cartinus <cartinus at xs4all.nl>  wrote:
> >Here is an example of a turn restriction. Both the secondary and the
> >unclassified road continue, but they are split at the crossing to make the
> >turn restriction relations.
> >
> ><http://www.openstreetmap.org/?lat=52.063909&lon=5.173566&zoom=18&layers=B
> >000FTF>
> 
> Okay, I see it but I don't understand it. What is that symbol in
> the intersection?

A traffic light

> I don't see it in the map key. What is a "turn
> restriction"?

I tells you how you may continue in an intersection. In this case you are not 
allowed to turn at all. Important information for routing software.

> How is it rendered differently from a typical
> intersection?

It isn't. At least not in Mapnik or Osmarender as far as I have seen.
-- 
/Per Lindström