Another type of electric assist motor, often referred to as the mid-drive system, is increasing in popularity. With this system, the electric motor is not built into the wheel but is usually mounted near (often under) the bottom bracket shell. In more typical configurations, a cog or wheel on the motor drives a belt or chain that engages with a pulley or sprocket fixed to one of the arms of the bicycle's crankset. Thus the propulsion is provided at the pedals rather than at the wheel, being eventually applied to the wheel via the bicycle's standard drive train.
The environmental credentials of e-bikes, and electric / human powered hybrids generally, have led some municipal authorities to use them, such as Little Rock, Arkansas with their Wavecrest electric power-assisted bicycles or Cloverdale, California police with Zap e-bikes. China’s e-bike manufacturers, such as Xinri, are now partnering with universities in a bid to improve their technology in line with international environmental standards, backed by the Chinese government who is keen to improve the export potential of the Chinese manufactured e-bikes.
The time or distance an electric bike battery will run between chargings is impossible to judge with much accuracy. There are too many variables: terrain, speed, rider weight, bike load (shopping, kids, luggage), and more. However, we can make a few generalizations about an e-bike’s recharge time and overall working life. These generalizations should be used for comparison purposes only.
Power assisted bicycles are classified in two categories in Saskatchewan. An electric assist bicycle is a 2 or 3 wheeled bicycle (sic.: 3 wheeled bicycle) that uses pedals and a motor at the same time only. A power cycle uses either pedals and motor or motor only. Both must have engines with 500 watt power or less, and must not be able exceed 32 km/h (20 mph), i.e., electric motor cuts out at this speed or cycle is unable to go this fast on a level surface. The power cycle has to meet the Federal Motor Vehicle Safety Standards for a power-assisted bicycle. The power cycle requires at least a learner's driving licence (class 7), and all of the other classes 1-5 may operate these also. The electric assist bicycle does not require a licence. Helmets are required for both. Both are treated as bicycles regarding rules of the road. Gas powered or assisted bicycles are classified as motorcycles regardless of engine size or if using pedals plus motor. Stickers identifying the bicycle's compliance with the Federal classification may be required for power cycles by some cities or municipalities. 
Having spent some quality time with Wing’s e-bike, I understand why so many people are excited about the growing popularity of electric-powered vehicles like bikes and scooters. They take a lot of the work out of getting from point A to point B, while retaining all of the joy. They can give you more confidence when navigating a treacherous city terrain that prioritizes cars over people. And let’s face it: bikes are cool, and always will be.
With a 150mm-travel RockShox Yari fork and 132mm of rear travel from the RockShox Monarch Plus R shock, the Remote CTRL is Kona’s first dual-suspension e-mountain bike. It’s powered by a 250-watt Bosch Performance Line XC mid-drive motor that uses the company’s progressive E-MTB mode that is adaptable to rider input, which means you don’t have to toggle through assistance modes while riding. It offers assistance up to 20 mph, and the 500Wh integrated battery is the largest Bosch currently offers. Beefy 27.5x2.8-inch Maxxis Recon tires offer plenty of traction and also help to absorb smaller hits.
China has experienced an explosive growth of sales of non-assisted e-bikes including scooter type, with annual sales jumping from 56,000 units in 1998 to over 21 million in 2008, and reaching an estimated fleet of 120 million e-bikes in early 2010. This boom was triggered by Chinese local governments' efforts to restrict motorcycles in city centers to avoid traffic disruption and accidents. By late 2009 motorcycles are banned or restricted in over ninety major Chinese cities. Users began replacing traditional bicycles and motorcycles and e-bike became an alternative to commuting by car. Nevertheless, road safety concerns continue as around 2,500 e-bike related deaths were registered in 2007. By late 2009 ten cities had also banned or imposed restrictions on e-bikes on the same grounds as motorcycles. Among these cities were Guangzhou, Shenzhen, Changsha, Foshan, Changzhou, and Dongguang.
Whether squeezing onto the 4 train or pedaling through Lower Manhattan, I notice a few curious glances at the bike with the big battery in the center of the frame. This is not surprising; e-bikes are huge practically everywhere but the US. According to the latest figures from the Confederation of the European Bicycle Industry, e-bike growth in the UK is up from 40,000 units in 2016 to 63,000 in 2017.
To qualify as an electric-assisted bicycle under state law they need to have a seat and fully operable pedals for human propulsion, meet federal motor vehicle safety standards, an electric motor that has a power output of not more than 1,000 watts, maximum speed of not more than 20 mph (electric motor and human power combined), disengages or ceases to function when the vehicle’s brakes are applied, two or three wheels