U turn restriction on an divided roads

The members of a relation restriction should be ways that start or end at the same node. In your example, Victoria Road East should end at the north stoplight; Church Street should start and end at the stoplights; and Victoria Road West should start at the south stoplights. To make this happen, split each of those three ways at the stoplight. (You may need to split Church Street twice, once at each stoplight.)

Then, add a relation using the iD editor. Choose one of the involved ways (for example, the west portion of Victoria Road East), scroll to the bottom, click the + button under "All relations", and click "New relation...". Choose "Restriction features" and then "No U-Turn". This will let you edit the restriction relation.

Firstly, add a "name" tag to the restriction (the value doesn't matter, as you'll see in a second). Then, under "All members", you should see the road you selected before. Set its role appropriately ("from" for Victoria Road East). Select the next relation member (the middle part of Church Street South), click the + button under "All relations", and choose "No U-turn foo", where "foo" is the name you entered previously. Set its role appropriately ("via").

Repeat this for Victoria Road West, and then, click the "No U-turn foo" relation name to edit the relation, and remove the temporary name you added earlier.

Here is a quick video I recorded showing how to map u-turns with divided lanes using the iD editor.

PS: If anyone knows of a better place to host please let me know.