Today beginning at around 6 PM, a group of a dozen or so older adolescents began riding motor bikes up and down Morningside Avenue between 123rd Street and 116th Street. They did not wear helmets, they had no license plates. They rode at very, very high speeds, did "wheelies," and one of them rode on the sidewalk at several points. They disturbed everyone around with their noise and prevented people from enjoying the park. The police were not in evidence for reasons that I do not understand. This went on for around forty-five minutes.