gridlock vs headway

gridlock

noun
  • any paralysis of a complex system due to severe congestion, conflict, or deadlock. 

  • A condition of total, interlocking traffic congestion on the streets or highways of a crowded city, in which no one can move because everyone is in someone else's way. 

  • On a smaller scale: the situation in which cars enter a signal-controlled intersection too late during the green light cycle, and are unable to clear the intersection (due to congestion in the next block) when the light turns red, thus blocking the cross traffic when it's their turn to go. Repeated at enough intersections, this phenomenon can lead to citywide gridlock. 

verb
  • To cause traffic congestion. 

headway

noun
  • The interval of time or distance between the fronts of two vehicles (e.g. buses) moving in succession in the same direction, especially along the same pre-determined route. 

  • Movement ahead or forward. 

  • Forward motion, or its rate. 

  • A cross-heading. 

  • The clearance beneath an object, such as an arch, ceiling or bridge; headroom. 

  • Progress toward a goal. 

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