If the aircraft is in flight, a steady green light signal from the control tower means cleared to land. If the aircraft is on the ground, it means cleared for takeoff. If the light is aimed at ground vehicles or foot traffic, steady green means cleared to cross the runway, or proceed.
clear for landing or takeoff.
A steady (instead of flashing) yellow light means the traffic signal is changing from green to red. You must stop if it's safe to do so. If you're already stopped you must not proceed.
Ground - Cleared for Takeoff. Air - Cleared to Land.
You get light green.
A red light - steady or flashing - means STOP. A steady amber light means Caution - signal about to change. A flashing amber light means SLOW DOWN.
Because a green light has a light bulb behind green plastic.
A traffic signal displaying a steady circular green light means that, at least according to the light, you have the right to proceed. BUT, that also means "only if it is safe to do so". For example, a driver coming South is in the intersection, going straight, when the light changes. Traffic stops him from getting out of the intersection. You are traveling west and want to turn South. But his Range Rover is in the intersection! You have the green light! What you do is stay put, even if your light changes to red before you can move into your turn, even if everyone behind you gets mad at you. You must not clog up the intersection, because drivers coming East may want to turn North.
Green light - Green, White light - Green, Red light - Black
warm front
steady amber
Diaphragm