mp3-tag is a small WPF application designed to add MP3 tags on your songs based on the folder hierarchy its contains in.
Right now, the path are coded in the following format:
path/{ALBUM}/{CD if any, not mandatory}/{TRACKNUMBER} - {ARTIST NAME} - {SONG-NAME}.mp3
This tool will then extract all those metadata from the file path and put them inside the MP3 tag to be read correctly by MP3 player like your car.