To effectively reduce the greenhouse gas emission, electric scooters have been developed and become a booming green transportation around the world. Most of these electric scooters possess a fixed reduction ratio in the powertrain, which makes them far from satisfactory-you can't have low cost, high performance and efficiency at the same time. However, as a silver bullet, one kind of two-speed transmission is developed. The two-speed transmission will shift automatically according to speed and throttle. An exquisite design with of a one-way clutch as well as a synchronizer effectively reduces the inevitable shocks while shifting. The electric scooter with such two-speed transmission will be launched on the market in 2013. This product successfully reaches the concept of high performance, high efficiency and rather low cost. The performance data of this scooter (equipped with 12″ tire), according to the test pattern of Taiwan E-scooter (TES), are 174kg in weight (including 75kg for driver), gradeability 17.8 degrees (32.1%), maximum speed 55.7 km/h, and efficiency 43.4 km/kWh.