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, US and Canada (see below))

Extend right arm straight out in the direction of the turn, parallel to the road.

Right Turn (US and Canada, as an option)

Extend your left upper-arm out to the left, parallel to the road and angle your forearm vertically upward. This follows automotive practice. The Uniform Vehicle Code in the US recognizes both this signal and the arm to the right signal for cyclists. State traffic laws generally conform to the Uniform Vehicle Code, but exceptions may exist.

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 and Canada)

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, Denmark)

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.