As one who enjoys riding my bicycle, I am amazed at the behavior of some cyclists. The other night, as I was coming home from the grocery store, I entered the roundabout on 116th Street and Keystone Parkway. As I got through the circle, I noticed a bicyclist up ahead. As it was around 5:30 p.m., traffic was heavy and continuous. Then, without any warning, this cyclist put out his arm and began turning in front of me from the bike lane. It was just one move: arm up and began turning. I tried to stop, groceries hit the floor of the car, but I needed to swerve out of his way. As I maneuvered, I could hear a very sarcastic, “Thank you!” from the cyclist. Much is written about aggressive vehicle drivers around bicycles, but just as a car must turn a signal on well before making a turn, a bicyclist also should give more warning of a turn across traffic.