Since 2001, Canada's Motor Vehicle Safety Regulations (MVSR) have defined Power Assisted bicycles (PABs). They are currently defined as a two or three wheeled bicycle with an attached electric motor of 500W or less and which is capable of being propelled manually. Furthermore to meet the safety requirements set down by this legislation it must meet the following; when engaged by muscular power it must cease assistance when muscular power ceases or if powered by an accelerator controller cease power when braking and be incapable of providing assistance above 32 km/h and bear a label that is permanently affixed by the manufacturer and appears in a conspicuous location stating the vehicle is a power-assisted bicycle.[5][6]

Some electric bikes claim to use a neat trick called regenerative braking. If you start pedaling the bicycle or going downhill, the spinning wheels turn the electric motor in the hub in reverse and start charging up the batteries. In practice, regenerative braking is nowhere near as useful on an electric bicycle as it is on an electric train or car. An electric bike has much less mass and velocity than either a train or car, so it never gains (or loses) anything like as much kinetic energy when it starts and stops. You'd have to go down an awful lot of hills to charge up the batteries completely and that's usually not practical. And what's the point in pedaling the wheels simply to charge the battery? You might as well have bought an ordinary bicycle to start with!
Some components, which are often optional accessories on sports bicycles, are standard features on utility bicycles to enhance their usefulness, comfort, safety and visibility. Mudguards, or fenders, protect the cyclist and moving parts from spray when riding through wet areas and chainguards protect clothes from oil on the chain while preventing clothing from being caught between the chain and crankset teeth. Kick stands keep bicycles upright when parked, and bike locks deter theft. Front-mounted baskets, front or rear luggage carriers or racks, and panniers mounted above either or both wheels can be used to carry equipment or cargo. Pegs can be fastened to one, or both of the wheel hubs to either help the rider perform certain tricks, or allow a place for extra riders to stand, or rest.[citation needed] Parents sometimes add rear-mounted child seats, an auxiliary saddle fitted to the crossbar, or both to transport children. Training wheels are sometimes used when learning to ride.

But electric bicycles—e-bikes—are new territory for me. Broadly speaking, there are two basic options in e-bike land: power-on-demand and pedal-assist. With the former, the rider can control the speed with a throttle instead of just pedaling. Think moped but with an electric motor instead of internal combustion. Pedal-assist, by contrast, requires the rider to do some of the work. The electric motor won't engage unless the rider is pedaling.
How do the State Laws relate to the 2001 Federal Law? This is a difficult question to answer and know how they apply to you individually. From the Federal Law, one would hope that your purchased ebike is simply classified as a bicycle, with all the rights and privileges allotted to a normal cyclist. However, State Laws are confusing because they may be more restrictive in parts and add other requirements. About 30 U.S. states still have confusing regulations around them. Either the bikes are technically classified as mopeds or motor vehicles, or they have equipment, licensing or registration requirements that cause problems for riders. Thanks to the People-For-Bikes/Bicycle Product Suppliers Association (BPSA) partnership with local advocacy groups, they have been able to make the case for streamlining state regulations so that e-bikes are essentially treated like regular bicycles.4
State and Local Laws dictate your use, but cannot constitutionally supersede the federal law – Any ebike purchased within the 750W/20mph limits has no fear of being under federal motor vehicle classification, nor can any state classify them a motor vehicle. The ebike is considered a ‘bicycle’ for consumer purposes. However, the State Laws on local bike paths and local thruways may prohibit or limit ebike access. When bike path signs use word such as ‘motor vehicles’ and ‘motorbikes’ , the laws are likely referring to gas-ICE motorbikes/dirt bikes/scooters, and not ebikes. Other references to ‘motorized bicycles’ or ‘motorized vehicles’ sound more inclusive and probably are intended for either ebikes or gas mopeds. If in doubt, you always have the option to pedal unassisted by completely powering your bike down. Even though Federal law grant ebikes a bicycle status, the common consensus found in my research allows local and state law to add additional regulation to pathway and road access, just because “it has a motor”. So the Federal laws protects the consumer from the burden of motor vehicle requirements, but not the restrictions to local and state right of ways enjoyed by all non-motored bicycles.
What's the Centros like? Big and heavy, but with enough power to overcome that, it really reminded me of a more upmarket Volt Pulse. You do tend to find that the weightier e-bikes give more of a feeling of speed, even though you're only doing 20mph or so at the absolute most (only up to 15mph with electrical assistance so you'll need leg muscles or a downward incline to get to that outlandish velocity).

Electric motorized bicycles can be power-on-demand, where the motor is activated by a handlebar mounted throttle, and/or a pedelec (from pedal electric), also known as electric assist, where the electric motor is regulated by pedaling. These have a sensor to detect the pedaling speed, the pedaling force, or both. An electronic controller provides assistance as a function of the sensor inputs, the vehicle speed and the required force. Most controllers also provide for manual adjustment.
On February 4, 2014, SB997 was introduced by Senator Matt Smith, which seeks to amend PA Vehicle Code to include "Pedalcycle with Electric Assist". In a memo addressed to all senate members, Smith said the definition shall include "bicycles equipped with an electric motor not exceeding 750 watts, weighing not more than 100 pounds, are capable of a maximum speed of not more than 20 mph, and have operable pedals."[128][129]

In Nova Scotia power-assisted bicycles are classified similarly to standard pedal bicycles. The Nova Scotia Motor Vehicle Act defines a power-assisted bicycle as a bicycle with an electric motor of 500 watts or less, with two wheels (one of which is at least 350 mm) or four wheels (two of which are at least 350mm). PABs are permitted on the road in the province of Nova Scotia as long as you wear an approved bicycle helmet with the chinstrap engaged. They do not have to meet the conditions defined within the Canadian Motor Vehicle Safety Regulations for a motorcycle (they are not classed as "motor vehicles"), but they do have to comply with federal regulations that define Power Assisted Bicycles.
An electric bicycle is a bicycle with an electric motor used to power the vehicle, or to assist with pedaling. In many parts of the world, electric bicycles are classified as bicycles rather than motor vehicles, so they are not subject to the same laws as motor vehicles. Electric bicycles are one type of motorized bicycle. However, electric bicycles are defined separately and treated as a specific vehicle type in many areas of legal jurisdiction.
Under the statute, mopeds must be registered. To be registered under Hawaii law a moped must bear a certification label from the manufacturer stating that it complies with federal motor vehicle safety standards (FMVSS). A moped must also possess the following equipment approved by the D.O.T. under Chapter 91: approved braking, fuel, and exhaust system components; approved steering system and handlebars; wheel rims; fenders; a guard or protective covering for drive belts, chains and rotating components; seat or saddle; lamps and reflectors; equipment controls; speedometer; retracting support stand; horn; and identification markings.

There are two main categories when choosing an e-bike: a pre-built electric bike or a custom e-bike conversion. Prefab electric bikes come in a wide variety of setups and styles and are designed specifically as electric bicycles. With unique characteristics and design qualities, most meet the law requirements which limit power and speed. There is also a variety of options to choose from equipped with different design and different motor and battery configurations to suit different riding styles and preferences: cruisers, commuters, mountain bikes and more. Pre-built e-bikes are clean and sleek in design with all of the wiring and electrical components built directly into the bike. For most people, production e-bikes work great and there’s no need for a custom conversion.

"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]
“Changes in production and consumption patterns are a crucial element of the sustainability agenda. Communication between product developers and users, and user integration in product development, can serve as a means for organizational as well as individual learning processes, resulting in sustainable product development. [...] Improved methods, such as INNOCOPE (innovating through consumer-integrated product development), tested in this study with a cycle manufacturer and resulting in a new product, a pedelec, are needed for effective communication, activating consumers and enabling them to promote sustainability goals. Through co-operative product development processes key factors facilitating and obstructing the adoption of sustainable innovations may be identified. Such processes can enhance the emergence and diffusion of sustainable product innovations and different forms and bodies of knowledge can be combined. Integrating users' contextual everyday knowledge of the product with the technical knowledge of companies may lead to mutual learning, technical innovations and changes in consumer behaviour.” (Hoffmann, 2007).
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.
The body is made from light and durable aluminum. The handlebar comes with simple controls to let you accelerate, brake, monitor battery life, operate headlights and of course…sound the horn. There’s even an USB point that will let you charge your iPhone or Android on the go. The bike can reach a top speed of 10mph. Feel the wind in your hair as you zoom up and down hills and past all that city traffic…
EU: EN15194 (EPAC – Electrically Power Assisted Cycles) defines the use pedal-assisted less than 25k/h bikes: "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 25 km/h or if the cyclist stops pedaling.” 

What an experience. I really had no idea what to expect when I first got on. The ride was smooth, and the assisting function was excellent and seamless. It is not like a motorcycle, it is just like a bike with some extra help. I felt completely safe on this bike, as well as comfortable in the seat. Especially in San Francisco with all the hills, going up the ramp felt like I was moving on a flat surface still. For commuters who might be worried about having to change clothes during an arduous commute in on their bike, fear not. This bike makes everything easy, and simple enough that you could ride to work in your work clothes and not fear getting too hot and sweaty. For those who have switched to the bike to decrease their impact on the environment, this bike is a must. Get there fast,
Further innovations increased comfort and ushered in a second bicycle craze, the 1890s Golden Age of Bicycles. In 1888, Scotsman John Boyd Dunlop introduced the first practical pneumatic tire, which soon became universal. Willie Hume demonstrated the supremacy of Dunlop's tyres in 1889, winning the tyre's first-ever races in Ireland and then England.[28][29] Soon after, the rear freewheel was developed, enabling the rider to coast. This refinement led to the 1890s invention[30] of coaster brakes. Dérailleur gears and hand-operated Bowden cable-pull brakes were also developed during these years, but were only slowly adopted by casual riders.
It is important to note that if a vehicle has an electric motor greater than 500 watts and is capable of powering the vehicle when traveling at a speed greater than 32 km/h and it does not have a CMVSS compliance label it cannot be registered unless the owner can prove, by having the vehicle certified by an engineer, that it is safe for operation on NB highways. Also, not all vehicles are suitable for operation on NB highways and it could be that the vehicle in question may not be a motor driven cycle or a bicycle and cannot be operated on the highway at all.

There's much less of a sensation of the Electrified S2 'fighting back' once you hit 15.5mph, as well. That's helped by the automatic 2-speed gear box, although this does take some getting used to. Because its cogs are very different sizes you can end up with all sorts of cadence problems as it auto-shifts from high back to low. With practice you can avoid this, or of course you could in theory fit a second cog that's closer in size to the first.

Maintenance of adequate tire inflation is the most frequent and troublesome concern for cyclists and many means and methods are employed to preserve pneumatic integrity. Thicker tires, thicker tubes, tire liners (of a number of rather impenetrable devices installed between the tire and tube), liquid sealing compounds squeezed into the tube, and automotive-style patch kits are all used to reliably contain the typical tire pressures of 40 to 60 pounds per square inch that are required for bicycle operation. Thin, light bicycle tires are particularly vulnerable to penetration and subsequent deflation caused by goat's heads and other burs, colloquially known as stickers. Inflation of bicycle tires to pressures higher than typical for automotive use requires special pumps. The complexity of bicycle tire maintenance and repair may cause many to not consider the bicycle for transport or leisure.
If you are a person who enjoys riding a bike casually at a typical bike path speed (10-15mph), and you like the idea of an ebike push up a hill, against the wind or to relieving a sore knee, then your market for a fully legally defined ebike is very broad and your practical use only has a few limitations. Most ebikes will meet your needs and expectation. I would estimate that 85% of the electric bikes on the market are 100% compliant meeting the federal definition. I encourage you to take the plunge and get a good quality ebike and ride more with assist. Do so with the confidence that electric bikes are here to stay. Coexisting with pedestrians and other cyclist will become a normal part of cycling life.