road sign vs waymark

road sign

noun
  • A sign for the control of traffic or the information of drivers. 

waymark

noun
  • A sign or symbol marked in a prominent position in an off-road location to show the track of a footpath or route; fingerpost; guidepost; milestone. 

  • A map coordinate stored within a satellite navigation system 

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