red light (traffic); red light; signal to stop; sign of danger
traffic light; signalling mechanism; semaphore (apparatus)
waiting for the traffic lights to change
pyrotechnic signal; signal flare
green light (traffic); green light; go-ahead signal; permission to go ahead (with something)
Morse code (esp. signalling)
ignoring a traffic light; red-light violation; running a red light; jaywalking
identifying signal; recognition signal; (radio) call sign
flash signal (e.g. between ships); flashing caution signal; accident warning signal
flag signaling; semaphore
warning signal; restricted speed signal
incoming signal; input signal
(pedestrian) crosswalk signal
yellow light (traffic); warning sign; sign of danger
signal transformation; signal shaping
signal strength; signal intensity; SS
acoustic signal; audible signal; audio signal
main signal; traffic signal
call sign (esp. maritime); distinctive letters
fixed-time traffic lights
clock signal; clock pulse
fixed-time traffic lights
luminance signal; Y signal
common channel signalling
physical communication control sublayer
SNR; signal to noise ratio
signal transformation; signal shaping
clock signal; clock pulse
advance warning of a traffic signal; preliminary traffic signal