kerb vs neutral ground

kerb

noun
  • The raised edge between the pavement and the roadway, typically made of concrete though originally consisting of a line of kerbstones. 

  • A stone ring built to enclose and sometimes revet the cairn or barrow built over a chamber tomb. 

verb
  • To damage vehicle wheels or tyres by running into or over a pavement kerb. 

  • To take a dog to the kerb for the purpose of evacuating. 

neutral ground

noun
  • The median strip or central reservation between lanes of traffic in a divided highway. 

  • Used other than figuratively or idiomatically: see neutral, ground. 

How often have the words kerb and neutral ground occurred in a corpus of books? (source: Google Ngram Viewer )