Legislative changes in 2012 significantly altered the classification and regulatory structure for e-bikes. The general effect was to establish electric-assisted bicycles as a subset of bicycles and regulate e-bikes in roughly the same manner as bicycles instead of other motorized devices with two (or three) wheels. Laws 2012, ch. 287, art. 3, §§ 15-17, 21, 23-26, 30, 32-33, and 41. The 2012 Legislature also modified and clarified regulation of e-bikes on bike paths and trails. Laws 2012, ch. 287, art. 4, §§ 1-4, 20.
It is important to note that if a vehicle has an electric motor greater than 500 watts and is capable of powering the vehicle when traveling at a speed greater than 32 km/h and it does not have a CMVSS compliance label it cannot be registered unless the owner can prove, by having the vehicle certified by an engineer, that it is safe for operation on NB highways. Also, not all vehicles are suitable for operation on NB highways and it could be that the vehicle in question may not be a motor driven cycle or a bicycle and cannot be operated on the highway at all.
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 bicycle's invention has had an enormous effect on society, both in terms of culture and of advancing modern industrial methods. Several components that eventually played a key role in the development of the automobile were initially invented for use in the bicycle, including ball bearings, pneumatic tires, chain-driven sprockets and tension-spoked wheels.
Oklahoma the following restrictions on the operation of Electric-Assisted Bicycle in 47 O.S. 11-805.2  as follows: 1. Possess a Class A, B, C or D license, but shall be exempt from a motorcycle endorsement; 2. Not be subject to motor vehicle liability insurance requirements only as they pertain to the operation of electric-assisted bicycles; 3. Be authorized to operate an electric-assisted bicycle wherever bicycles are authorized to be operated; 4. Be prohibited from operating an electric-assisted bicycle wherever bicycles are prohibited from operating; and 5. Wear a properly fitted and fastened bicycle helmet which meets the standards of the American National Standards Institute or the Snell Memorial Foundation Standards for protective headgear for use in bicycling, provided such operator is eighteen (18) years of age or less.
The federal Consumer Product Safety Act defines a "low speed electric bicycle" as a two or three wheeled vehicle with fully operable pedals, a top speed when powered solely by the motor under 20 mph (32 km/h) and an electric motor that produces less than 750 W (1.01 hp). The Act authorizes the Consumer Product Safety Commission to protect people who ride low-speed electric vehicles by issuing necessary safety regulations. The rules for e-bikes on public roads, sidewalks, and pathways are under state jurisdiction, and vary.