(ii) a vehicle equipped with two or three wheels, foot pedals to permit muscular propulsion, and an independent power source providing a maximum of 2 brake horsepower. If a combustion engine is used, the maximum piston or rotor displacement may not exceed 3.05 cubic inches, 50 centimeters, regardless of the number of chambers in the power source. The power source may not be capable of propelling the device, unassisted, at a speed exceeding 30 miles an hour, 48.28 kilometers an hour, on a level surface. The device must be equipped with a power drive system that functions directly or automatically only and does not require clutching or shifting by the operator after the drive system is engaged.
On a trip to Palo Alto last year, we had the chance to ride Specialized’s pedal-assisted Turbo Vado and the model is still our favorite ebike on the market. Utilizing a 350-watt motor and 604-watt-hour lithium-ion battery, the Turbo Vado is capable of traveling a whopping 80 miles on a single charge, which should be more than enough for any daily commute with plenty of miles left over.
A human traveling on a bicycle at low to medium speeds of around 16–24 km/h (10–15 mph) uses only the power required to walk. Air drag, which is proportional to the square of speed, requires dramatically higher power outputs as speeds increase. If the rider is sitting upright, the rider's body creates about 75% of the total drag of the bicycle/rider combination. Drag can be reduced by seating the rider in a more aerodynamically streamlined position. Drag can also be reduced by covering the bicycle with an aerodynamic fairing. The fastest recorded unpaced speed on a flat surface is 144.18 km/h (89.59 mph)
However, laws and terminology are diverse. Some countries have national regulations but leave the legality of road use for states and provinces to decide. Municipal laws and restrictions add further complications. Systems of classification and nomenclature also vary. Jurisdictions may address "power-assisted bicycle" (Canada) or "power-assisted cycle" (United Kingdom) or "electric pedal-assisted cycles" (European Union) or simply "electric bicycles". Some classify pedelecs as distinct from other bikes using electric power. Thus, the same hardware may be subject to many different classifications and regulations.
On October 22, 2014 PA house bill 573 passed into law, which is Act 154, which changes the definition of "pedalcycle" (bicycle) in the PA state vehicle code. "Pedalcycle" is now defined as a vehicle propelled solely by human-powered pedals or a "pedalcycle" (bicycle) with electric assist( a vehicle weighing not more than 100 pounds with two or three wheels more than 11 inches in diameter, manufactured or assembled with an electric motor rated no more than 750 watts and equipped with operational pedals and travels at speeds less than 20 mph). This bill allows the usage of pedal assisted bicycles in PA that follow the adopted state guidelines.
In general, more expensive bikes are better. However, this is just a trend. E.g. the "Kassensturz" Consumer program from our state TV found in a 2012 study confined to an engineering school, that "Supermarket" bikes, e.g. the 1400 CHF (1200 Euro) "Leopard" bike from COOP did very well. Evaluation is "good" (almost the same as the three times more expensive 25km/h Stromer). They also pointed out a very bad model from a discounter. In other words, you can find good cheap models, but read the tests first.