Traffic lights
At busy junctions, coloured lamps control traffic flow from different directions.
Lamps are switched by flow-monitoring sensors and software, or by pedestrians (where it would otherwise be difficult for them to cross a road). Lamp lights are circular :
Lamps are switched by flow-monitoring sensors and software, or by pedestrians (where it would otherwise be difficult for them to cross a road). Lamp lights are circular :
RED means stop at the thick white line nearby. So does AMBER, unless it's unsafe. Even when GREEN, you must give way to pedestrians, and go only if it's safe.
If there's no WHITE LINE nearby, the traffic light is a "repeater signal" placed further into a junction, to help vehicles already beyond the white line while they wait for a safe gap to turn right.
(Don’t confuse these with lights you come across after turning left or right past a green light: they may be set back from the corners of the junction to allow longer vehicles to make the turn. These are repeaters for the traffic NOW behind you, waiting at a red light).
Also, green "filter lights" allow cars to move in the direction of a lit arrow without needing to give way (such as in the first picture).
If there's no WHITE LINE nearby, the traffic light is a "repeater signal" placed further into a junction, to help vehicles already beyond the white line while they wait for a safe gap to turn right.
(Don’t confuse these with lights you come across after turning left or right past a green light: they may be set back from the corners of the junction to allow longer vehicles to make the turn. These are repeaters for the traffic NOW behind you, waiting at a red light).
Also, green "filter lights" allow cars to move in the direction of a lit arrow without needing to give way (such as in the first picture).