footbridge vs trestle

footbridge

noun
  • A bridge over a road, railway, river, etc for pedestrians. 

trestle

noun
  • A trestle bridge. 

  • A folding or fixed set of legs used to support a tabletop or planks. 

  • A framework, using spreading, divergent pairs of legs used to support a bridge. 

  • A horizontal member supported near each end by a pair of divergent legs, such as sawhorses. 

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