Traffic light/single warning light
Traffic lights follow a universal colour code which alternates the right of way accorded to users with a sequence of illuminating lamps or LEDs of three standard colours:
Green light
Allows traffic to proceed in the direction denoted, if it is safe to do so and there is room on the other side of the intersection.[6][7][8]
Red light
Prohibits any traffic from proceeding. A flashing red indication requires traffic to stop and then proceed when safe (equivalent to a stop sign).
Amber light (also known as 'orange light' or 'yellow light')
Warns that the signal is about to change to red, with some jurisdictions requiring drivers to stop if it is safe to do so, and others allowing drivers to go through the intersection if safe to do so. In some European countries (such as the UK), red and amber is displayed together, indicating that the signal is about to change to green.
A flashing amber indication is a warning signal. In the United Kingdom and Ireland, a flashing amber light is used only at pelican crossings, in place of the combined red–amber signal, and indicates that drivers may pass if no pedestrians are on the crossing.
In some countries traffic signals will go into a flashing mode if the conflict monitor detects a problem, such as a fault that tries to display green lights to conflicting traffic. The signal may display flashing amber to the main road and flashing red to the side road, or flashing red in all directions. Flashing operation can also be used during times of day when traffic is light, such as late at night