Basic arm and hand signals when driving include pointing the right arm out and rotating it clockwise to indicate a right turn or rotating it anticlockwise to indicate a left turn. Moving the arm repeatedly up and down displays the intention to slow down or stop.
These directional signals can be used when turning or changing lanes. Arm signals are used with all vehicles, including cars, motorcycles, bicycles and buses. Motorcyclists can use their left arm to indicate a left turn as opposed to turning their right arm anticlockwise. Authorised persons also use signals to indicate certain things to drivers, such as lifting one arm up to show that traffic is coming from the front, or one arm up and one to the side to indicate that traffic is approaching from the front and back. The slowing down signal is used commonly when a driver sees something that other drivers may not see due to reduced visibility.
Hand signals are typically used when the electronic signalling system of a vehicle is not functioning correctly or if an indicator bulb is broken. Different countries have different rules and regulations about hand and arm signals, such as whether the palm or forearm should be facing up or down.