carriageway vs hard shoulder

carriageway

noun
  • The part of a road that carries traffic. 

  • One side of a dual carriageway that carries traffic in a single direction. 

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 carriageway and hard shoulder occurred in a corpus of books? (source: Google Ngram Viewer )