Signals are how you communicate your intentions to other road users. The examiner is constantly watching whether your signals are timely, clear, and appropriate for the situation. Poor signalling is one of the most common reasons for serious faults on driving tests.
You must signal in good time before every turn, lane change, or manoeuvre. Signalling too late gives other road users no time to react. Signalling too early can be misleading, for example, indicating left before a junction when there is a side road on the left before your turn. The rule is to signal when you would expect another road user to benefit from knowing what you are about to do.
Always check your mirrors before signalling. If you signal without checking, you may create a dangerous situation, for example, a cyclist may be alongside you when you indicate to turn left. The MSM routine (mirror, signal, manoeuvre) is the foundation of safe signalling.
Cancel your signal after you have completed the manoeuvre. A left signal that stays on after you have turned can mislead following drivers into thinking you are pulling over. A right signal that stays on can mislead oncoming traffic. Most cars have self-cancelling indicators, but they do not always work perfectly, especially in gentle bends. Check your dashboard indicator light to confirm the signal has cancelled.
Brake lights are also a form of signal. They tell following drivers that you are slowing down. Use progressive braking rather than sudden harsh braking so drivers behind have time to react. If you brake sharply without warning, the driver behind may not be able to stop in time.
Arm signals are rarely needed in modern driving but can be useful if your indicators fail or if you are in a situation where other road users may not see your lights. To signal left, extend your left arm out of the window horizontally. To signal right, extend your left arm out and bend it upwards at the elbow. To signal slowing down or stopping, extend your left arm out and bend it downwards at the elbow.