Is there a way to export OpenStreetMap public transport routes to a KML or KMZ file? I'm trying to view the routes in another application (Google Earth) which supports KML data, but doesn't support the OpenStreetMap API.
Check out the Overpass Turbo API. Use the wizard to simply search for your desired OpenStreetMap routes using their location or the route's osm-id and then press the export-tab. There you can choose "KML" as an export format.