"Bicycles" and "Electric Bicycles" are legally defined in the Texas Transportation Code Title 7, Chapter 551 entitled "Operation of Bicycles, Mopeds, and Play Vehicles" in Subchapter A, B, C, and D.[131] Under Chapter 541.201 (24), "Electric bicycle" means a bicycle that is (A) designed to be propelled by an electric motor, exclusively or in combination with the application of human power, (B) cannot attain a speed of more than 20 miles per hour without the application of human power, and (C) does not exceed a weight of 100 pounds. The department or a local authority may not prohibit the use of an electric bicycle on a highway[132] that is used primarily by motor vehicles. The department or a local authority may prohibit the use of an electric bicycle on a highway used primarily by pedestrians.

Electric bicycles have two main methods of operation: pedal-assist and/or throttle-control. As the name implies, pedal-assist “assists” your pedaling and requires some input. With this method, a torque sensor picks up movement or stress to determine the power requirements of the rider. Everything is automated so there’s nothing to think about, just jump on and start riding. Some bikes have multiple settings, while others have just one setting with the addition of a throttle control. Depending on the setting, pedal-assistance can help a little – or a lot. At lower settings, pedal-assist is barely noticeable but helps extend your range. At higher settings, the power is quite obvious and feels like a strong wind at your back with the motor doing most of the work while you pedal along.
If you are an experienced rider this is actually annoying as hell. Personally, I tend to leave whatever I'm riding in a high gear all the time, because my body is like a powerful machine, and I found the way it slowed my escape from the lights quite disconcerting. For beginners, it could be useful, but it's worth remembering that the whole point of e-bikes is that the motor helps you along anyway, so I do really question the usefulness of this.
E-bike usage worldwide has experienced rapid growth since 1998. In 2016 there were 210 million electric bikes worldwide used daily.[33] It is estimated that there were roughly 120 million e-bikes in China in early 2010, and sales are expanding rapidly in India, the United States of America, Germany, the Netherlands,[2] and Switzerland.[34] A total of 700,000 e-bikes were sold in Europe in 2010, up from 200,000 in 2007 and 500,000 units in 2009.[35]

Photo: This typical electric bicycle, a Sanyo Eneloop (now discontinued), had a range of about 30–55 km (17–35 miles) and a top speed of around 24 km/h (15 mph). Note the 250-watt hub motor on the front wheel and the 5.7Ah lithium-ion battery pack (black, marked "Sanyo," just in front of the back wheel). Picture by kind permission and courtesy of Richard Masoner, originally published on Flickr under a Creative Commons (CC BY-SA 2.0) licence.

These small complaints prove that the Rad Wagon isn’t perfect. But its overwhelmingly positive qualities clearly outweigh the drawbacks. The Rad Wagon handled beautifully on city streets, accelerating with ease and maintaining a charge for extended range. Rad Power bikes also offers an array of helpful accessories—think racks, baskets, panniers, and platforms—that make the bike nearly as convenient as a car. Time and time again I passed cars stuck in traffic on their daily commute and couldn’t help but wondering: Why don’t more people switch from cars to an e-bike?
Flyer Vollblut. A new rear motor bike from one of the most reliable E-bike makers. This model doesn't look as "heavy" as most other Flyer models. The Vollblut 500 has the 500W new Panasonic rear motor, front fork suspension, 28 inch wheels. It is in the same price range as the Stöckli and the Stromer. Flyer is known for top service and reliability, but it's a new model with a new motor ....
As the managing editor of Ars Technica, one of my duties is to monitor the daily torrent of news tips and PR emails. The overwhelming majority of them is deleted after a glance, and the news tips and story ideas are passed along to the appropriate writer. Sometimes a product announcement will catch my eye, and I will follow up. Once in a blue moon, I'll say, "please send me one so that I may review it." And that's how I ended up riding an electric bike around the Chicago suburbs for two weeks.
The basic shape and configuration of a typical upright or "safety bicycle", has changed little since the first chain-driven model was developed around 1885.[7][8][9] However, many details have been improved, especially since the advent of modern materials and computer-aided design. These have allowed for a proliferation of specialized designs for many types of cycling.
The electric bike revolution has officially crossed into the arena of off-road motorbikes. For those who prefer riding in nature, Cake introduced a product which not only respects the environment but other riders, as well. Cake’s Kalk is a silent off-road motorbike that releases no emissions into the atmosphere. Additionally, its electric motor means no gear changing or clutching — a silent motorbike that won’t detract from the experience of others. Perhaps the best part is Cake avoided any sacrifice in performance. The Kalk reaches speeds of fifty miles per hour and features three distinct driving modes: Discover, Explore, and Excite.

Photo: Could solar power be the future of electric bicycles? The large solar panel mounted over the back wheel of this experimental bike powers an electric motor connected by a chain drive to the back wheel, helping the rider when he doesn't feel like pedaling. Using clean, green solar power would remove the problem of having to charge electric bikes with electricity generated from fossil fuels—and help to extend their range significantly. Photo by Warren Gretz courtesy of US DOE/NREL.

The two most common electric motor styles used in today’s e-bikes are hub motors and mid-drive motors. The Freedom uses a hub motor, which was located in the center of the rear wheel. Hub motors typically don’t offer the same natural maneuverability as the increasingly more common (and more expensive) mid-drive motors because their weight is concentrated in the rear of the bike. It can be jarring when the motor prevents you from going faster than the allotted speed, especially when cruising downhill, but 20 mph is the legal maximum for e-bikes in the US. (In the EU, it’s even lower: 25 km/h, or 15.5 mph.)
This year was busy at Haibike’s EUROBIKE stand. The reason: the new FLYON series, which we could only admire behind glass. The new bikes are the spearhead of Haibike’s eMTB development with an exciting and unprecedented level of integration and connectivity. They have a specially developed display, their own remote and, thanks to a 5,000 lumen headlight, are able to turn night into day. To make the rider visible at all times, taillights are neatly integrated into the frame. The bikes also come with the most powerful motor currently available on the market, from TQ Systems. We are sure that many will buy this bike not only for its performance but also as a status symbol.
In 5 years of working as a bike messenger in Minneapolis, I've ridden all kinds of bikes, in all kinds of weather. I've ridden walmart mountain bikes, 80's classic steel road bikes, kitted out Treks, pretty much everything EXCEPT for fat tire bikes. Such wide tires always seemed... too much. No need for a bike that only makes itself worthwhile maybe two months out of the year, I thought.
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.
Brock had been running his esoteric shop on Cambie St. for over 30 years, pioneering the sale and production of recumbent bikes, tricycles, velomobiles, unicycles, and of course electric bicycles well before any of these things were popular. He was dabbling with early ebike conversions in the 1990's when we were still in grade school and has been for many years one of the few shops always willing to say yes to electric retrofits. We hope to still see him riding around streets of Vancouver in a white velomobile. 
An itinerant wordsmith with a broad constellation of interests, Lydia Chipman has turned iconoclasm into a livelihood of sorts. Bearing the scars and stripes of an uncommon diversity of experience -- with the notable exceptions of joining a religious order or becoming an artist -- she still can’t resist the temptation to learn something new. Lydia holds a master of arts in English from Georgia Southern University, and a bachelor of arts cum laude in integrative studies from Clayton College. Her expertise is in the areas of robotics, electronics, toys, and outdoors and computer equipment.
The legal definition/description of an electric bicycle is most closely described in the code as a "motorized scooter" in that it is powered by an electric motor and/or human power [45]. It may be also be described as a "Motorized bicycle". However, that description does not include electric powered motor specifically. And it appears that the legal definition "Motorized Bicycle" and "Motorized Scooter" are in conflict. Motorized bicycle is a pedal bicycle which has a helper motor, or a non-pedal bicycle which has a motor, with a cylinder capacity not exceeding fifty cubic centimeters, an automatic transmission, and which is capable of a maximum speed of no more than thirty miles per hour. A motorized bicycle shall not be operated upon any way, as defined in section one within the commonwealth by any person under sixteen years of age, nor at a speed in excess of twenty-five miles per hour. A motorized bicycle shall not be operated on any way by any person not possessing a valid driver’s license or learner’s permit. Every person operating a motorized bicycle upon a way shall have the right to use all public ways in the commonwealth except limited access or express state highways where signs specifically prohibiting bicycles have been posted, and shall be subject to the traffic laws and regulations of the commonwealth and the regulations contained in this section, except that the motorized bicycle operator may keep to the right when passing a motor vehicle which is moving in the travel lane of the way, and the motorized bicycle operator shall signal by either hand his intention to stop or turn. Motorized bicycles may be operated on bicycle lanes adjacent to the various ways, but shall be excluded from off-street recreational bicycle paths. Every person operating a motorized bicycle or riding as a passenger on a motorized bicycle shall wear protective headgear conforming with such minimum standards of construction and performance as the registrar may prescribe, and no person operating a motorized bicycle shall permit any other person to ride a passenger on such motorized bicycle unless such passenger is wearing such protective headgear.
This article did a good job of trying to justify the assist speed limits but fell short of detailing how that can ever be effectively enforced. In reality the only enforcement that is going to work is applied speed limits to use of bikes and ebikes. For example, it makes sense that a bike lane on a street that the speed limit of vehicles is the speed limit of the bikes/ebikes. On sidewalks and shared pedestrian paths the speed limit probably does need to be in the 15-20mph range to match traditional bikes speeds on those paths.
A new European product safety standard EN 15194 will be published in 2009. EN 15194 contains several new requirements for ebikes to be sold in European Union and European Economic Area, including weight and voltage limitations. EN 15194 also defines a specific name for EU approved electrically-assisted cycles, EPAC - "Electrically Pedal Assisted Cycle".
DON'T BUY THIS BIKE!!!!! Worst customer service ever!!! I bought this bike for my 18 year old son to commute to school. It worked well for the first 2 months but the battery is cheap and stated to wear out. I tried going on the website, but they battery shows as out of stock, and has been for 3 months now. I left 5 emails with customer service, never got a reply. Also there is no number listed on their website to even speak to a real person. Now I have a worthless 5 month old bike..... horrible this company should be ashamed.

Our hope is that this plug will become to motors in the 500-1500 watt power range what the 9pin Z910 became for the low power geared motors, with all motor manufacturers agreeing to the same pinout standard for easy swapping and interchangeability . We have an L10 version of the Phaserunner motor controller available now and will soon be expanding this to a Grinfineon offering as well.
Earlier UK regulations required that the motor has an average power output limited to 200 W (250 W for tricycles and tandems) and weight limited to 40 kg (60 kg for tricycles and tandems). These regulations must come in-line with the EU regulations by (find deadline). For models sold before June 2003, e-bikes conforming to the speed, weight and power limits may also be considered pedal cycles. Electric bikes with higher power outputs, or those not meeting the "pedelec" definition are now treated as motorcycles and require a license.

Controllers for brushless motors: E-bikes require high initial torque and therefore models that use brushless motors typically have Hall sensor commutation for speed and angle measurement. An electronic controller provides assistance as a function of the sensor inputs, the vehicle speed and the required force. The controllers generally allow input by means of potentiometer or Hall Effect twist grip (or thumb-operated lever throttle), closed-loop speed control for precise speed regulation, protection logic for over-voltage, over-current and thermal protection. Bikes with a pedal assist function typically have a disc on the crank shaft featuring a ring of magnets coupled with a Hall sensor giving rise to a series of pulses, the frequency of which is proportional to pedaling speed. The controller uses pulse width modulation to regulate the power to the motor. Sometimes support is provided for regenerative braking but infrequent braking and the low mass of bicycles limits recovered energy. An implementation is described in an application note for a 200 W, 24 V Brushless DC (BLDC) motor.[43]
As long as you can do without some of the perks that pricier models offer—like a detailed display unit, integrated lights, and a torque-sensor motor—the August Live! LS is a solid, stable, comfortable, and really freakin’ cute (have you see those polka-dot fenders?) e-bike. Its 8-speed twist shifter, chopper-style handlebar, Touch Down Geometry (for a more laid-back ride), and three levels of assist keep this bike within the realm of “cruiser.” But with a 250-watt Bafang rear-hub motor, a top pedal-assisted speed of 20 mph, and reliable disc brakes, the August is no joke. It’ll get you to the top of relatively steep climbs without forcing you out of the saddle, and it feels super stable on the way back down. It has a battery range of 20 miles, but that’s enough to take it where it’s happiest: tootling along at the beach, around town, and through the park.
In built up cities around the world, urban planning uses cycling infrastructure like bikeways to reduce traffic congestion and air pollution.[59] A number of cities around the world have implemented schemes known as bicycle sharing systems or community bicycle programs.[60][61] The first of these was the White Bicycle plan in Amsterdam in 1965. It was followed by yellow bicycles in La Rochelle and green bicycles in Cambridge. These initiatives complement public transport systems and offer an alternative to motorized traffic to help reduce congestion and pollution.[62] In Europe, especially in the Netherlands and parts of Germany and Denmark, bicycle commuting is common. In Copenhagen, a cyclists' organization runs a Cycling Embassy that promotes biking for commuting and sightseeing. The United Kingdom has a tax break scheme (IR 176) that allows employees to buy a new bicycle tax free to use for commuting.[63]
At the top end, the 20mph speed limit isn't an absolute, like the speed of light. It's just the most you'll get from the motor. I was able to get it up to 28mph on a flat road (there are no other roads where I live) in Turbo mode and 8th gear, but it took hard work to get there and maintain the speed. The easiest comparison is my mountain bike, where I've hit 23mph on that same stretch of road—and that took a heck of a lot of effort. Exactly how much effort does it take to ride? I have a 15-mile route that I ride on both my mountain bike and cyclecross bike. According to my Apple Watch, I generally burn around 1,400 or so calories on a brisk ride. I'll probably average around 13mph or so on my Marlin and between 16 and 17.5mph on my XO2. I averaged 14.9mph and burned a hair over 1,000 calories with the Bulls Cross E8.
All classes of electric-assisted bicycles may be operated on a fully controlled limited access highway. Class 1 and 2 electric bicycles can be used on sidewalks, but Class 3 bicycles "may not be used on a sidewalk unless there is no alternative to travel over a sidewalk as part of a bicycle or pedestrian path."[143] Generally a person may not operate an electric-assisted bicycle on a trail that is designated as non-motorized and that has a natural surface, unless otherwise authorized.
The last 8 months we've been wrapping up some long duration testing of Statorade across different hub motor lines and performing experiments confirming its long term stability. These results have us pumped to introduce this motor cooling solution beyond DIY'ers and into wider markets. As an example, have a look at the video we below showing the effect this has on a small direct drive folding bike motor.