Traffic Lights

Traffic Lights

Many junctions are busy with traffic traveling in several directions. One way to control the flow of traffic is with traffic lights. Junctions with traffic lights come in many different shapes and sizes. This app illustrates some of the most common scenarios, and demonstrates the basic techniques for dealing with these junctions safely.

What do the colours mean?

Red: A red traffic light means you must stop if you have not already crossed the solid white line. If there is a cycle box in front of you, there should be two solid white lines. You may have already crossed the first line, but not the second, when the light changes to red. In this case you should stop before crossing the second line.

Red & Amber: Red & amber lights showing together means the green light is about to show. You have a few seconds in which to prepare for moving. This is a good time to set the gas and find the biting point. Your left hand should be on the handbrake, ready to release it.
Green: A green traffic light means you may proceed, but only if it is safe to do so. If turning right, priority should be given to oncoming traffic as usual.

Filter arrows: Some junctions use filter arrows to give priority to road users traveling in a particular direction. Filter arrows may point left, right or ahead.


If a round green light is showing, traffic may proceed as normal in all directions regardless of any filter arrows, whether the arrows are illuminated or not.


If a green filter arrow pointing to the right appears in addition to a round green light, traffic turning right is now being given priority over oncoming traffic. After checking it is safe, anyone waiting to turn right can proceed unimpeded.

Amber: An amber traffic light means you must stop before the solid white line if it is safe to do so. Whether it is safe or not will depend on a number of factors such as the speed you are traveling, the distance to the line and the presence and distance of following traffic.


It is important to know what is behind you when you make a decision whether or not to stop for an amber light. It is preferable to stop, but if another vehicle is close behind you, you must consider the possibility that to stop may be more dangerous than it would be to continue through the junction.

Important points to remember

Always think ahead and try to anticipate traffic lights changing. For example, if you are looking at a green light, think about the possibility it may change to amber at any moment.

Be aware of all other road users, particularly pedestrians, cyclists and motorcyclists. Remember that others may not obey the traffic lights or other signs and road markings. Pedestrians may walk into the road without warning. Cyclists and motorcyclists can be hard to see. They can come from behind you as well as ahead or from the side.
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