parking lot vs viaduct

parking lot

noun
  • A road blocked by stop-start traffic. 

  • An open area, generally paved, where automobiles may be left when not in use. 

viaduct

noun
  • A bridge with several spans that carries road or rail traffic over a valley or other obstacles. 

How often have the words parking lot and viaduct occurred in a corpus of books? (source: Google Ngram Viewer )