[Tagging] Missing only_u_turn?

[Nathan Edgars II]

On 6/18/2011 10:21 PM, Alan Mintz wrote:
> On the turn restrictions page, there is no mention of only_u_turn, yet
> I've found these to exist in the real world.

I don't get it. 
http://www.openstreetmap.org/browse/relation/1630619/history is the only 
one you've added - can you really not continue east on Alessandro? 
(Aside: why the zigzagging? Intersections on divided highways should be 
represented as two nodes.) I'm also not clear on what source_ref = 
AM909_DSCX7666 mean.