Under the terms of the Vienna Convention on Traffic, bicycles are considered to be vehicles and cyclists are considered to be drivers. The traffic codes of most countries reflect this.

Similar to automobile signaling, there are three primary signals:

Left Turn: Extend left arm straight out in the direction of the turn, parallel to the road.

Right Turn (UK, Ireland, Italy, Australia): Extend right arm straight out in the direction of the turn, parallel to the road.

Right Turn(US): Extend your left upper-arm out to the left, parallel to the road and angle your forearm vertically upward.

Stopping/Braking (UK and Ireland): Extend your right arm directly out to the right parallel to the road with palm facing down and slowly wave the extended arm up and down.

Stopping/Braking (US): Extend your left upper-arm out to the left, parallel to the road and angle your forearm vertically downward.

Stopping/Braking (Italy): Extend your right arm vertically, with palm facing forward.

Stopping/Braking (Australia): Extend your right arm vertically, with palm facing forward, or, extend your right upper-arm out to the right parallel to the road and make your forarm vertical with your palm facing forward.