[Talk-us] tagging cul-de-sacs

Martijn van Exel mvexel at gmail.com
Tue Apr 10 15:17:22 BST 2012

On 4/10/2012 7:46 AM, Peter Dobratz wrote:
> I'm experimenting with the Java code from Traveling Salesman
> http://wiki.openstreetmap.org/wiki/Traveling_salesman
> I'm making library calls to the routing code and it seems that the
> router does not understand cul-de-sacs mapped as a single
> self-intersecting way. This got me thinking about different ways to
> possibly map cul-de-sacs.  I generally use Way with
> highway=residential or highway=unclassified.  At the end of the road
> there is a loop that intersects the same Way.  Here is one that I
> recently mapped:
> http://www.openstreetmap.org/browse/way/158307363
> Is this how people generally map these things?

No, I ususally tag the end node highway=turning_circle. There are so 
many of them littered around US suburbia that mapping each and every one 
of them as a circular way would make for a lot of not too useful data, 
not to mention a lot of work.

> One other possibility that I could think of was splitting the circular
> part at the end and tagging it junction=roundabout.  However, this
> would imply that the road is one-way, and I'm not sure that that is
> the case.  Typically there is no one way sign on the ground and people
> feel free to travel in either direction on these (though being a
> cul-de-sac they don't have a lot of traffic).

A roundabout (or mini_roundabout) implies to me (although it is not 
defined on the wiki) that there is more than one entry / exit road. So 
intuitively I'd say that is not an appropriate tag.

Martijn van Exel

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