Merging parallel ways that are part of the same street using GeoJSON leaflet

I am using leaflet, for routing transit GeoJSON routes, Major routes polylines are divided into two separate Inbound and Outbound routes, parallel ways - one way for each direction.

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How can merge the parallel ways into a single way running down the center of the street ?

Right now I'm using "https://github.com/bbecquet/Leaflet.PolylineOffset" this library for showing transit bus routes