Hello!
Thank you for your comment. Our initiative is called "Road Attributes", and it focuses on improving the quality of OSM road data including turn lanes — with the goal of enhancing the accuracy and usefulness of the map overall. You can find more information about our project here-https://github.com/mapbox/mapping/issues/425. We do not have local knowledge indeed, but we rely on OSM wiki and analyze the sources which are appropriate for mapping on OSM (satellite and street-level imagery, for example). We’re targeting to have as accurate data as possible, so in case of lack of information or experience, we’re not going to add any data.
I’d really appreciate it if you could clarify the specific issue you corrected, so that we can better understand it and make sure we avoid similar mistakes in the future. Our goal is to make valuable contributions to OSM and to work in line with mapping standards.

Best regards, Natallia