In the United States electric bikes have seen slow but steady growth since the late 90’s and as a result, in 2001 congress was lobbied and passed the first and only bill to define ebikes in federal law. This law, 107-319, exempts electrified bicycles with operating pedals using motors under 750 watts limited to 20 mph from the legal definition of a motor vehicle.2.

The bicycle is also used for recreational purposes, such as bicycle touring, mountain biking, physical fitness, and play. Bicycle competition includes racing, BMX racing, track racing, criterium, roller racing, sportives and time trials. Major multi-stage professional events are the Giro d'Italia, the Tour de France, the Vuelta a España, the Tour de Pologne, and the Volta a Portugal.

I found that by sticking it on 'Turbo' or 'Sport' mode (the upper 2 of the 4 electrical assistance levels) and leaving it in a middle gear, the Centros felt zippy when in full flight, but able to pull away from the lights with no problems. Less lazy riders than me might want to actually use the 10 gears, and will find that in the top gear, it's quite easy to push past the mandated 15.5mph electrical limit.
Chart: Electric bicycles are rapidly becoming popular. This chart shows the growth in sales of what the manufacturers refer to as "electric power-assisted cycles (EPACs)" in European countries over the last decade. Over 1.6 million electric bikes were sold in Europe in 2016 alone, which is about 7 percent of total European bicycle sales. What this chart doesn't reveal is that the bikes are much more popular in some countries than others: four countries accounted for 70 percent of all the sales (Germany, 36 percent; the Netherlands, 16 percent; Belgium, 10 percent; and France 8 percent). Data sourced from the report "European Bicycle Market: 2017", courtesy of CONEBI (Confederation of the European Bicycle Industry). These are the newest figures available at the time this article was last updated (September 2018).
Übrige "Motorfahrräder": “E-Bikes mit einer Leistung zwischen 500 und 1000 Watt oder einer bauartbedingten Höchstgeschwindigkeit von 20 bis 30 km/h oder einer Tretunterstützung, die auch bei einem Tempo von 25 – 45 km/h wirkt, gelten als Motorfahrräder und benötigen ein entsprechendes Kontrollschild.”. You can use any bicyle path and also hiking roads forbidden to motorbikes if you drive slowly.
Under Arizona law, motorized electric bicycles and tricycles meeting the definition under the applicable statute are not subject to title, licensing, insurance, or registration requirements, and may be used upon any roadway authorized for use by conventional bicycles,[77] including use in bike lanes integrated with motor vehicle roadways. Unless specifically prohibited, electric bicycles may be operated on multi-use trails designated for hiking, biking, equestrian, or other non-motorized usage, and upon paths designated for the exclusive use of bicycles. No operator's license is required, but anyone operating a bicycle on Arizona roads must carry proof of identity.[78] A "motorized electric bicycle or tricycle" is legally defined as a bicycle or tricycle that is equipped with a helper motor that may be self-propelled, which is operated at speeds of less than twenty miles per hour. Electric bicycles operated at speeds of twenty miles an hour or more, but less than twenty-five miles per hour may be registered for legal use on the roadways as mopeds, and above twenty-five miles per hour as a registered moped with an 'M' endorsement on the operator's driving license. However, mopeds in Arizona are prohibited from using bike lanes on motor vehicle roadways. The Arizona statute governing motorized electric bicycles does not prohibit local jurisdictions from adopting an ordinance that further regulates or prohibits the operation of motorized electric bicycles or tricycles.[79]
In New Zealand, the regulations read: "AB (Power-assisted pedal cycle) A pedal cycle to which is attached one or more auxiliary propulsion motors having a combined maximum power output not exceeding 300 watts."[56] This is explained by NZTA as "A power-assisted cycle is a cycle that has a motor of up to 300 watts. The law treats these as ordinary cycles rather than motorcycles. This means that it is not necessary to register or license them.[57] Note that the phrase "maximum power output" that is found in the regulation (but omitted in the explanation) may create confusion because some e-bike motor manufacturers advertise and print on the motor their "maximum input power" because that number is larger (typically motors run at about 80% efficiency [58]) thus give the impression the buyer is getting a more powerful motor. This can cause misunderstandings with law enforcement officers who do not necessarily understand the difference, and when stopping a rider on an e-bike in a traffic stop, look at the number on the motor to determine if the e-bike is legal or not.
But the good times of the stealthy ebike existence will not endure forever. The ebike market is growing steadily and more so, technology is driving performance up and costs down. The market for a green, lifestyle friendly, transportation technology, with GPS, theft ID, cell service and probably skim lattes is alive and driving an emerging market. It is a matter of time before we all must face and respond to the legal demands of the state and local laws. Not to be over obligatory about being legal and duty oriented, but I do call on my fellow ebikers to ride legal, whether ebike, moped or other. Go ahead and build the 1200W ebike of your dreams, but get it insured and licensed if you must. Such compliance will set the precedence for public acceptance of ebikes in general, and build a track record for expansion and mainstreaming of moped-speed ebikes for commuter value driven needs of the future.
As electric bike options continue to expand, more brands are integrating the battery more seamlessly. That makes them look sleeker (and more like a real bike). Batteries are expensive, so make sure there’s a good way to lock the battery to your bike if you’ll be keeping it outside. Overall weight is important. Some battery and motors can add 15 pounds or more to the bike. With assist, you won’t feel that much when you’re riding, but you will if you have to carry your bike up stairs or lift it onto a bike rack.
And let’s not forget the economic advantages of owning an e-bike. The annual cost of running a new family car is, on average, about $9,000 per year. Running an electric bike costs around $400 per year. And while filling a gas tank costs around $30, recharging an electric bike battery costs only about 50 cents. A tank of gas may get you further, but not 60 times further!