blacktop vs slip road

blacktop

noun
  • A road so paved. 

  • Asphalt concrete or similar bituminous black paving material used for the surface of roads (e.g., tarmacadam, tarmac). 

  • A paved area on a schoolground reserved for recess activities, often doubling as a parking lot. 

verb
  • To pave with blacktop. 

slip road

noun
  • A segment of roadway that joins a motorway to ordinary roads (in either direction) 

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