"Electric power-assisted bicycle" means a vehicle that travels on not more than three wheels in contact with the ground and is equipped with (i) pedals that allow propulsion by human power and (ii) an electric motor with an input of no more than 1,000 watts that reduces the pedal effort required of the rider. For the purposes of Chapter 8 of this title, an electric power-assisted bicycle shall be a vehicle when operated on a highway.[65]
Different gears and ranges of gears are appropriate for different people and styles of cycling. Multi-speed bicycles allow gear selection to suit the circumstances: a cyclist could use a high gear when cycling downhill, a medium gear when cycling on a flat road, and a low gear when cycling uphill. In a lower gear every turn of the pedals leads to fewer rotations of the rear wheel. This allows the energy required to move the same distance to be distributed over more pedal turns, reducing fatigue when riding uphill, with a heavy load, or against strong winds. A higher gear allows a cyclist to make fewer pedal turns to maintain a given speed, but with more effort per turn of the pedals.
There's no question that electric bikes are far better for the environment than petrol-powered car engines. But that doesn't mean they're completely perfect. Making and disposing of batteries can be very polluting. Not only that, but an electric bicycle is still using energy that has to come from somewhere. You may think you're using clean green power, but the electricity you use for getting about might have come from a filthy old, coal-fired power plant or one driven by nuclear energy. (If you're lucky, of course, it might have come from solar panels or a wind turbine!) Electric bikes are nowhere near as environmentally friendly as ordinary push bikes, but nothing is ever perfect—and, as people often say, "the perfect is the enemy of the good." Electric bikes are certainly a step in the right direction. If everyone used them to get about instead of cars, global warming might be less of a problem, and the world would be a far cleaner and healthier place!

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)[41]
Ontario is one of the last provinces in Canada to move toward legalizing power-assisted bicycles (PABs) for use on roads, even though they have been federally defined and legal in Canada since early 2001. In November 2005, "Bill 169" received royal assent allowing the Ministry of Transportation of Ontario (MTO) to place any vehicle on road. On October 4, 2006, the Minister of Transportation for Ontario Donna Cansfield announced the Pilot Project allowing PABs which meet the federal standards definition for operation on road. PAB riders must follow the rules and regulations of a regular bicycles, wear an approved bicycle helmet and be at least 16 years or older. There are still a number of legal considerations for operating any bicycle in Ontario.[23][24][25]
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.
Haibike ships the HardNine with 29-inch tires, 180-millimeter hydraulic disc brakes, a 100-millimeter front suspension fork, and a nine-speed Shimano shifting system. The bike’s LCD readout is affixed to the handlebars and displays the current speed, level of charge, remaining range, and current pedal assist mode. The company says the battery can be completely recharged in just four hours, minimizing downtime between rides.