hard shoulder vs parkway

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) 

parkway

noun
  • A scenic freeway. 

  • A tree lawn. 

  • A divided highway with a landscaped median. 

  • a railway station built on the edge of a town, typically with a large car park to function as a park and ride interchange. 

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