Despite the illegal status in the state of New York, enforcement of this law varies at the local level. New York City enforces the bike ban with fines and vehicle confiscation for throttle activated electric bikes. However, Mayor Bill de Blasio has recently changed the city's official policy to legalize pedal-assist electric bikes that have a maximum speed limited to 20 mph.  Contrarily, Tompkins County supports electric bike usage, even providing grant money to fund electric bike share/rental projects.
The recommendation depends a lot on what you plan to use the bike for and how you plan to ride. That said, I would recommend at least a 750 (if not 1,000) watt motor, and, if you want reasonable range, 48 or 52v cells with a minimum rating of 19ah. For shorter rides, you can use a smaller battery. Multiply battery voltage by amp hour rating to get battery watt hours. Divide the watt hours by the motors power rating to get a general idea of how many hours of heavy use you might get. I’d also recommend a mid drive as opposed to a hub drive, or to find a hub drive wheel rated to take your and the bicycle's combined weight.
The first regularly produced device resembling the modern bicycle was unveiled in 1818. It was called the Dandy Horse. The two-wheeled ride-on Dandy Horse was the brainchild of German inventor Baron Karl Drais, and it featured a handle bar, a padded seat, and two inline wheels of nearly equal size. What it did not feature were pedals; this was a "running machine," thus its name in German, Laufmachine. The Dandy Horse saw only a flicker of popularity, and was largely an historical footnote within a handful of years, though its design is nearly mimicked in the child's balance bike of today.
The 1968 Vienna Convention on Road Traffic of the United Nations considers a bicycle to be a vehicle, and a person controlling a bicycle (whether actually riding or not) is considered an operator. The traffic codes of many countries reflect these definitions and demand that a bicycle satisfy certain legal requirements before it can be used on public roads. In many jurisdictions, it is an offense to use a bicycle that is not in a roadworthy condition.
Several bills have been sponsored to legalize electric bicycles for use on NYS roads, and several have overwhelmingly passed at the committee level, but none of these initiatives has been able to be heard and then passed in the New York State Senate, until 2015. The latest bill S3997, "An act to amend the vehicle and traffic law, in relation to the definition of electric assisted bicycle. Clarifying the vehicle and traffic law to define electric assisted bicycles; establish that electric assisted bicycles, as defined, are bicycles, not motor vehicles; and establish safety and operational criteria for their use." has passed in the Senate for the first time ever in 2015. The related Assembly bill A233 was not brought to a vote in the assembly even though it had passed with little issue in prior years.
But in Great Britain, the European Union definition is applicable, and the tighter restrictions of the Electrically Assisted Pedal Cycle Regulations 1983 (including a 200 kg weight limit on solo bicycles) were removed on 6 April 2015 by the Electrically Assisted Pedal Cycles (Amendment) Regulations 2015. Riders must be at least 14 years of age, but no driving licence is required.
Many countries have enacted electric vehicle laws to regulate the use of electric bicycles. Countries such as the United States and Canada have federal regulations governing the safety requirements and standards of manufacture. Other countries like the signatories of the European Union have agreed to wider-ranging legislation covering use and safety of their term EPAC (electric vehicles)
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. Soon after, the rear freewheel was developed, enabling the rider to coast. This refinement led to the 1890s invention 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.
In Australia the e-bike is defined by the Australian Vehicle Standards as a bicycle that has an auxiliary motor with a maximum power output not exceeding 200 W without consideration for speed limits or pedal sensors. Each state is responsible for deciding how to treat such a vehicle and currently all states agree that such a vehicle does not require licensing or registration. Various groups are lobbying for an increase in this low limit to encourage more widespread use of e-bikes to assist in mobility, health benefits and to reduce congestion, pollution and road danger. Some states have their own rules such as no riding under electric power on bike paths and through built up areas so riders should view the state laws regarding their use. There is no licence and no registration required for e-bike usage.
Electric bicycle fits under the definition of "moped" under Kentucky law. You don't need tag or insurance, but you need a driver's license. "Moped" means either a motorized bicycle whose frame design may include one (1) or more horizontal crossbars supporting a fuel tank so long as it also has pedals, or a motorized bicycle with a step-through type frame which may or may not have pedals rated no more than two (2) brake horsepower, a cylinder capacity not exceeding fifty (50) cubic centimeters, an automatic transmission not requiring clutching or shifting by the operator after the drive system is engaged, and capable of a maximum speed of not more than thirty (30) miles per hour Helmets are required.
Electrically-assisted cycles are usually classified as either pedelecs or e-bikes. Under European Union regulations adopted in the UK in June 2003, only power-assisted cycles meeting the pedelec classification are considered to be pedal cycles. The maximum power allowed in the European Union for (pedelec) electric bicycles is 250 W, with a maximum assisted speed of 25 km/h.. To meet the pedelec specification the electric motor must be activated by the rider's pedalling effort and the power must cut out completely whenever the rider stops pedalling. Control of the motor by pedalling is often the key difference between a pedelec and e-bike.
Simple, convenient, cheap, and economical—bicycles are one of the world's favorite forms of transportation. But they're not for everyone. They can be hard to pedal up and down hills or with heavy loads, and elderly or disabled people may find them impossible to manage. In the last few years, a new generation of electric bicycles has begun to revolutionize our idea of environmentally friendly transportation. These new cycles have all the convenience of cars with all the simple economy of ordinary cycles. Let's take a closer look at how they work.