so if I build a interchange (roundabout also) I can choose between 1, 2 or 3 lanes?

As said in discription it gives option which roads to use.

What does this mod do? I just wanna know if its does anything except left hand traffic?

@AraxEthyr Its main purpose was to make vanilla street constructions be able to have left hand traffic, in combination with my Left Hand Traffic mod. But it also adds the possibility of making the ramps 2 lanes instead of just one, and that is the reason I made it into a separate mod.

I can't see what this mod does.

Can you please explain clearly what is "bus right line", "passengers right line" and "tyres right line" type of roads? I can understand words, but what that all will do with traffic exactly? How this work with stops? With trams?