FC 1) We successfully recruit 80 low-income 4th and 5th grade children for the pilot Bicycle Train cluster RCT FC 2) The intervention children participate in the Bicycle Train program on average twice/week or more FC 3) Algorithms analyzing concurrent GPS and accelerometer data have high agreement, i.e. >90% agreement, with heart rate data/direct observation in distinguishing children's cycling-related physical activity duration and intensity from other physical activities and riding in a motor vehicle