As I’ve been working on updating the area around the university I work for, I’ve noticed that many of the street labels have multiple instances of the label showing up at very close intervals. I figured that this was happening because the streets are made up of line segments that aren’t connected somehow. However I am having trouble figuring out how to connect them into a single long line segment, short of deleting them all and starting over (which I don’t want to do). Any ideas? Thanks.
Never mind. I figured it out. I had to select one route, hold down shift and select the other and the “+” symbol would show up. I was trying to connect the end points instead of the lines. Turned out it was simpler than I thought. 
You have to be careful not to merge 2 road segments with different properties (e.g. surface, maxspeed, access rules)
Remember we never map for the renderer, so it’s up to the renderer to find an algorithm to minimise the number of labels, not the mapper.
happy mapping
And also those, which belong to different relations.
You better switch to JOSM, it checks for this error when merging ways.
It seems that you’ve destroyed many turn restrictions with the following changeset: http://www.openstreetmap.org/changeset/26690870
Please do not merge any ways with iD. Merging with iD is a mess as you get no warnings if you damage something.
It seems to me that the id editor needs to be disabled until things like this are fixed. It is a bit disappointing to have well intentioned new mappers destroying the data so easily.
Instead of complaining about iD, you should revert the changeset. If you know JOSM, you know it is easy.
Of course I’ve tried to revert the changeset, but when I got 7 conflicts I’ve stopped reverting.
There seems to be an old Github issue: https://github.com/openstreetmap/iD/issues/1512
Maybe we should revive it?