Electric bikes come in two categorys. The first is called Pedalics (pedal electric cycle) made by the Merida company which requires the rider to pedal the bike to engage the motor. The harder you pedal the more power the motor delivers. The power assist principle is similiar to the power steering in your car. Try parking a car with manual steering. Lots of work is needed from you compared to a car with power assisted steering. This is the principle of the pedalic only instead of turning a steering wheel you are pelalling a bike. As you press the pedals the power kicks in just like your autos power steering does. These bikes are amazing!! As you start off the motor gives you a boost to get underway. You always have an easy time pedaling even when approching steep hills. The computer senses the resistance and kicks in the power making the hill non-existant!! The pedelics offer the rider exercise and increases your physical range by power assisting you. The power assist is variable according to the need of the rider. Need more power? Just pedal a little harder and you have it. The computer works in total harmony with the rider delivering the right amount of power at the right time. You have never riden a machine quite like a pedelic. You will simply love these bikes!!
These bikes are totally legal in the United States. The US Senate has passed SR 1156, clearing the way for a legal definition of an electric bicycle in the USA. President Bush has signed this law. The new law will assign the governance of electric bicycles to the Consumer Product Safety Commission, and will define a bicycle that has pedals, (and is capable of being propelled by those pedals) an electric motor of no more than 750 watts, and a top speed (on motor only) of 20 mph as a "bicycle."
The second type are closer to the power control of a scooter. The ETC bikes have a power pack with friction drive motor that mounts in a rear rack. These bikes can be driven by motor, pedaling or both. The motor is controlled by a handle bar mounted lever. As with the Pedalics these are also totally legal.