hard shoulder vs lay-by

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) 

lay-by

noun
  • A paved area at the side of a highway designated for drivers to stop in, for emergency parking, or where vehicles can wait, with larger lay-bys possibly having facilities like food vendors or public telephones. 

  • A railroad siding; a second, short railroad track just to the side of a railroad track, connected with the main track by a switch and used for unloading, bypassing, etc. 

  • A method of retail purchase in which the selected goods are set aside and the customer pays for them in instalments, receiving them when fully paid; layaway. 

  • A widened section of a narrow river or canal, formed to one side so as to leave the channel free, for mooring of vessels, where vessels can lay over or allow others to pass. 

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