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.
E-bikes are classified in three different types: Class 1 and Class 3 bikes are powered proportionally to the “input” a rider gives via pedaling. “It feels natural, and you’re still riding a bike, so all your reflexes, skill and comfort you’ve developed over years of riding bikes apply immediately,” says Fritz Rice, sales manager of Gregg’s Cycles, near Greenlake.
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.
No endorsement is required on a driver license in order to operate a motorized bicycle, thus the motorized bicycle may be operated by anyone with a valid driver license. Goggles, windshields and other special equipment required for motorcycles and motor-driver cycles are not required for operation of a motorized bicycle. However, crash helmets are required regardless of operators age. Minors between the ages of 14 and 16 may apply for a restricted license to operate a motorized bicycle, just as they would to operate a motor-driver cycle. For instance, they must take a written test, vision tests and demonstrate their ability to operate the motorized bicycle. The license issued will be restricted to a motorized bicycle only. The license is valid only during daylight hours and within a seven-mile (11 km) radius of the driver's home. Applicants for any type of license less than eighteen (18) years old, must complete a Minor/Teen-age Affidavit and Cancellation form making the parent or legal guardian financially liable for the applicants action. 
Since cyclists' legs are most efficient over a narrow range of pedaling speeds, or cadence, a variable gear ratio helps a cyclist to maintain an optimum pedalling speed while covering varied terrain. Some, mainly utility, bicycles use hub gears with between 3 and 14 ratios, but most use the generally more efficient dérailleur system, by which the chain is moved between different cogs called chainrings and sprockets in order to select a ratio. A dérailleur system normally has two dérailleurs, or mechs, one at the front to select the chainring and another at the back to select the sprocket. Most bikes have two or three chainrings, and from 5 to 11 sprockets on the back, with the number of theoretical gears calculated by multiplying front by back. In reality, many gears overlap or require the chain to run diagonally, so the number of usable gears is fewer.
Stöckli E.T. Urban Confort, made in Switzerland. It has SwissGoDrive motors and Samsung batteries. There is a 500W/17.6Ah combo that seems to be ideal for commuters, i.e. it has a 50km range using full assistance. In the USA, a similar product is available as Currie eFlow e3 Nitro (different motor and electronics). This model doesn't have a front wheel suspension, but comes with "balloon" tires that somewhat absorb shocks. Options are available through types: "simple"/Urban/CROSS and man/confort models. E.g. the Cross model has a front suspension, a 500W motor and no equipment like lights, fenders, etc. However, paying extra, you can compose your own configuration. If you commute using bumpy roads, then get a front suspension.
Electric bikes aren’t just a practical and environmentally conscious solution to gridlock, they also are really fun to ride. On top of all of the persuasive arguments to get an electric bike, I think the Rad Wagon’s best-selling point comes down to enjoyment. Zooming down the street each morning I wasn’t angrily yelling at fellow drivers or rushing not to be late. The bike commute was part of the journey each day, and not just the means I used to get around. There’s a reason so many people loved biking as a kid, and it can be just as fun as an adult.
As is the case with any e-bike assembled from Chinese parts, Wing has its share of clones that can be found for sale on sites like IndieGoGo and Kickstarter. For example, the Danish company Strom Bikes has a model for city biking that also looks incredibly similar to Wing’s Freedom — and is apparently several hundred dollars cheaper too. This is also commonly found with electric scooters, with startups buying Chinese-made models and rebadging them for sale in the US.
None of this would matter if the VanMoof Electrified S2 (and its close relative the X2) wasn't fun to ride, but it is a blast. Like the Brompton, it pulls off the neat trick of powering you along but giving the illusion that you're doing the work, reacting quickly and cleverly to the speed of your pedalling and the difficulty of any incline you're on.