The key to riding your bike safely in traffic is to let cars around you know what you're doing. In this video, Dan, an REI Outdoor School instructor demonstrates proper hand signals that help you to be predictable. When you want to turn left, point left with your left arm. When you want to turn right, either point right with your right arm, or raise your left arm bent up at the elbow. To signal that you're slowing down or stopping, lower your left arm bent at the elbow. Slow down and maintain control of your bike when signaling, as signaling requires you to take one hand off the brakes.