Most European bike rules are tight and restrictive. Right now the California state ebike rules in AB 1096 provide the clearest and cleanest format, and they support ebike riding. No other U.S. regulations come close. The big brand ebikes (Giant, Specialized, Trek) are selling bikes that fit within European rules (250w-300w motors). This gives them economies of scale.
The environmental effects involved in recharging the batteries can of course be reduced. The small size of the battery pack on an e-bike, relative to the larger pack used in an electric car, makes them very good candidates for charging via solar power or other renewable energy resources. Sanyo capitalized on this benefit when it set up "solar parking lots", in which e-bike riders can charge their vehicles while parked under photovoltaic panels.[66]
The Super Commuter is very aptly named. The 350w Bosch motor will help you sustain speeds of up to 28mph, and the burly, 2.4-inch wide, Schwalbe Super Moto-X 650b tires will keep you secure on even the roughest city streets, and Shimano Deore hydraulic brakes provide ample stopping power. Fenders provide welcome protection from road spray so you arrive at your destination fresh, integrated lights are critical for post-sunset riding, and a side-view mirror hanging on the left side of the handlebar gives a great view of traffic around you. After all, you can ride at the speed of urban traffic on the Super Commuter.

European Union directive 2002/24/EC exempts vehicles with the following definition from type approval: "Cycles with pedal assistance which are equipped with an auxiliary electric motor having a maximum continuous rated power of 0.25 kW, of which the output is progressively reduced and finally cut off as the vehicle reaches a speed of 25km/h (15.5mph) or if the cyclist stops pedaling." This is the de facto definition of an electrically assisted pedal cycle in the EU. As with all EU directives, individual member countries of the EU are left to implement the requirements in national legislation.

Vehicles exceeding any of the criteria above must be registered and titled as a motorcycle. Other types of vehicles, such as electric scooters, "pocket rockets" and mini-choppers, may fit the definition of a moped or a motorcycle, but cannot be registered by the Department of State if they lack the equipment required by law to legally drive on public roads.[101]
Bicycle manufacturing proved to be a training ground for other industries and led to the development of advanced metalworking techniques, both for the frames themselves and for special components such as ball bearings, washers, and sprockets. These techniques later enabled skilled metalworkers and mechanics to develop the components used in early automobiles and aircraft.
In the United States electric bikes have seen slow but steady growth since the late 90’s and as a result, in 2001 congress was lobbied and passed the first and only bill to define ebikes in federal law. This law, 107-319, exempts electrified bicycles with operating pedals using motors under 750 watts limited to 20 mph from the legal definition of a motor vehicle.2.
Depending on local laws, many e-bikes (e.g., pedelecs) are legally classified as bicycles rather than mopeds or motorcycles. This exempts them from the more stringent laws regarding the certification and operation of more powerful two-wheelers which are often classed as electric motorcycles. E-bikes can also be defined separately and treated under distinct Electric bicycle laws.
Historically, women's bicycle frames had a top tube that connected in the middle of the seat tube instead of the top, resulting in a lower standover height at the expense of compromised structural integrity, since this places a strong bending load in the seat tube, and bicycle frame members are typically weak in bending. This design, referred to as a step-through frame or as an open frame, allows the rider to mount and dismount in a dignified way while wearing a skirt or dress. While some women's bicycles continue to use this frame style, there is also a variation, the mixte, which splits the top tube laterally into two thinner top tubes that bypass the seat tube on each side and connect to the rear fork ends. The ease of stepping through is also appreciated by those with limited flexibility or other joint problems. Because of its persistent image as a "women's" bicycle, step-through frames are not common for larger frames.
"Electric-assisted bicycle" means a bicycle with two or three wheels, a saddle, fully operative pedals for human propulsion, and an electric motor. The electric-assisted bicycle's electric motor must have a power output of no more than one thousand watts, be incapable of propelling the device at a speed of more than twenty miles per hour on level ground, and be incapable of further increasing the speed of the device when human power alone is used to propel the device beyond twenty miles per hour.[66]
Electric-assisted bicycles are treated as human-powered bicycles, while bicycles capable of propulsion by electric power alone face additional registration and regulatory requirements as mopeds. Requirements include electric power generation by a motor that cannot be easily modified, along with a power assist mechanism that operates safely and smoothly. In December 2008, The assist ratio was updated as follow: