Bicyclists are requested to use hand and arm signals with their left hand and arm. This will alert drivers, pedestrians, and other cyclists of their plans to veer from riding in a straight line.
Bikers are required to use signals for left and right turns, as well as stops. This is meant to alert others on the road. However, bicyclists are not required to signal, if removing their left hand from the handlebars might cause them to lose control of the bike.