Instead of code @marczoutendijk I propose to use this code in overpass:

[out:csv ("name")][timeout:2500];
{{geocodeArea:Leuven}}->.searchArea;
(
  way["highway"]["name"](area.searchArea);
);
for (t["name"])
{
  make street name=_.val;
  out;
}

http://overpass-turbo.eu/s/WzT
Code above returns street names in Leuven also but each street name is listed only once. In this way for Leuven there is only 1101 street names instead 28000 :slight_smile: