blacktop vs trunk 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. 

trunk road

noun
  • An important main road used by long-distance traffic, as well as heavy lorries. 

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