to switch-traffic-lights
  let horizontals patches with [signal? != nobody and (dir = "W" or dir = "E")]
  let verticals patches with [signal? != nobody and (dir = "S" or dir = "N")]

  switch-list-traffic-lights horizontals
  switch-list-traffic-lights verticals

end

to switch-list-traffic-lights [lights]
  ask lights[
    set ticks-signal ticks-signal + 1
  ]

  ifelse [signal?] of one-of lights = "red-light" and [ticks-signal] of one-of lights >= 50 + 4
  [
    ask lights[
      set ticks-signal 0
      set pcolor green
      set signal? "green-light"
    ]
  ]
  [
    ifelse [signal?] of one-of lights = "orange-light" and [ticks-signal] of one-of lights >= 4
    [
      ask lights[
        set ticks-signal 0
        set pcolor red
        set signal? "red-light"
      ]
    ]
    [
      if [signal?] of one-of lights = "green-light" and [ticks-signal] of one-of lights >= 50
      [
        ask lights[
          set ticks-signal 0
          set pcolor orange
          set signal? "orange-light"
        ]
      ]
    ]
  ]
end


to signal-event
  switch-traffic-lights
end