high road vs throughway

high road

noun
  • A main road or highway. 

  • Used other than figuratively or idiomatically: see high, road. 

  • A course of action which is dignified, honourable, or respectable. 

throughway

noun
  • A broad highway fit for high-speed traffic; a thoroughfare. 

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