driver's compartment vs landau

driver's compartment

noun
  • Synonym of cab (compartment at the front of a truck or train for the driver). 

landau

noun
  • A style of automobile based around the design of landau carriages. 

  • A type of lightweight, four-wheeled carriage in which the front and back passenger seats face each other. 

How often have the words driver's compartment and landau occurred in a corpus of books? (source: Google Ngram Viewer )