||This article contains instructions, advice, or how-to content. (July 2010)|
Hand signals are given by cyclists and some motorists to indicate their intentions to other traffic. 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.
In some countries (such as in the Czech Republic, Canada, and the USA), hand signals are designated not only for cyclists, but for every vehicle that does not have signal lights or has damaged signal lights. For example, drivers of older cars and mopeds may be required to make hand signals.
Similar to automobile signaling, there are three primary signals:
Left turn/overtaking 
- All Countries
- Extend left arm straight out in the direction of the turn, horizontally.
Right turn 
- UK, Germany, Ireland, Italy, Croatia, Russia, Australia, US and Canada (see below)
- Extend right arm straight out in the direction of the turn, horizontally.
- US and Canada, (optional)
- Extend your left upper-arm out to the left, horizontally 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. British Columbia (Canada) recognizes both.
Arm to the right has the advantage that it is more visible to any traffic likely to be affected, for example vehicles in the next lane to the right or also intending to turn right. It is also easier to teach to children: "point in the direction you are going to turn."
- UK and Ireland
- Extend your right arm directly out to the right horizontally with palm facing down and slowly wave the extended arm up and down.
- US and Canada
- Extend your left upper arm out to the left, horizontally and angle your forearm vertically downward.
- Extend your right arm vertically, with palm facing forward.
- Australia, Denmark
- Extend your right arm vertically, with palm facing forward, or extend your right upper arm out to the right horizontally and make your forearm vertical with your palm facing forward (as depicted in the US right turn signal above).
Conflict with brake operation 
A bicycle's front brake lever is typically installed on the side of the handlebar closest to the center of the road (front-left for right-side driving.) In many countries, the hand signal for stopping/braking requires that the cyclist signal with the hand used for the front brake. The front brake is the most effective method of stopping a bike under normal road conditions.
Cyclists, like all other road users, should be ready to make an emergency stop at all times. When approaching a junction a cyclist may wish to "cover the brake" in readiness for an emergency stop. It is not possible to cover both brakes when performing a hand signal and both hands are needed on the handlebars to steady the bicycle under hard braking. Cyclists therefore sometimes have to choose between giving a hand signal and covering the brake.