belt loop vs ring road

belt loop

noun
  • A highway that loops around the perimeter of a major city. 

  • The 'D' shaped frame of a belt buckle 

  • One of the loops of fabric ringing the waist of a pair of pants, used to hold the belt in place. 

ring road

noun
  • A circumferential highway around a town, city, or other conurbation. 

How often have the words belt loop and ring road occurred in a corpus of books? (source: Google Ngram Viewer )