blockage vs road block

blockage

noun
  • Synonym of constipation (“impairment of feces passage”). 

  • The thing that is the cause of such a state, blocking a passage. 

  • The state or condition of being blocked. 

  • Synonym of thrombosis, synonym of thromboembolism, or synonym of embolism. 

road block

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