footpath vs hard shoulder

footpath

noun
  • A paved path located at the side of a road for the use of pedestrians. 

  • Any set path or trail to be used by people walking. 

hard shoulder

noun
  • A verge to the side of a highway, which should be used only in case of an emergency (especially on a motorway) 

How often have the words footpath and hard shoulder occurred in a corpus of books? (source: Google Ngram Viewer )