Merging highways with two strokes into single path using QGIS

Question

In QGIS some of my vector layers (shapefiles) for roads have two paths. For highways, I assume this is for divided lanes, but I only want a single path to make it easier to style in Illustrator.

How can I combine the paths into a single one?

Answer 1

You can do this simply by installing a plugin named Topology checker. You should define a rule to delete parallel lines with a tolerance of n meters. Then delete or merge all the closely-paralleled lines. A thorough guide could be found here. Good luck.