Despite the illegal status in the state of New York, enforcement of this law varies at the local level. New York City enforces the bike ban with fines and vehicle confiscation for throttle activated electric bikes. However, Mayor Bill de Blasio has recently changed the city's official policy to legalize pedal-assist electric bikes that have a maximum speed limited to 20 mph.  Contrarily, Tompkins County supports electric bike usage, even providing grant money to fund electric bike share/rental projects.
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.
As of 2005, where Federal funds have been used in the construction of bicycle or pedestrian paths motor vehicles including electric bicycles (here defined as having a motor weighing less than Template:Convert) are not permitted unless State or Local regulations permit . This was known as the Transportation Equity Act for the 21st Century (TEA-21), or Public Law 105-178, or by its 2003 re-authorization which expired in 2005 the Safe, Accountable, Flexible, Efficient Transportation Equity Act (SAFETEA-LU).
(ii) a vehicle equipped with two or three wheels, foot pedals to permit muscular propulsion, and an independent power source providing a maximum of 2 brake horsepower. If a combustion engine is used, the maximum piston or rotor displacement may not exceed 3.05 cubic inches, 50 centimeters, regardless of the number of chambers in the power source. The power source may not be capable of propelling the device, unassisted, at a speed exceeding 30 miles an hour, 48.28 kilometers an hour, on a level surface. The device must be equipped with a power drive system that functions directly or automatically only and does not require clutching or shifting by the operator after the drive system is engaged.
"Medical Exemptions" are also a standard right in the State of Texas for motorcycles & even bicyclists. Through Texas's motorcycle helmet law (bicycle helmet laws from city ordinances), it is only required for those 21 years old or younger to wear a helmet. However, a medical exemption, written by a certified licensed medical physician or licensed chiropractor, which exempts one from wearing a helmet, can be used for bicyclists if helmets are required.
"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. 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 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.
Depending on local laws, many e-bikes (e.g., pedelecs) are legally classified as bicycles rather than mopeds or motorcycles. This exempts them from the more stringent laws regarding the certification and operation of more powerful two-wheelers which are often classed as electric motorcycles. E-bikes can also be defined separately and treated under distinct Electric bicycle laws.
What I found most interesting is how my cycling habits changed over my two weeks with the eBike, mostly for the better. In most states, cyclists need to come to a complete stop at stop signs... and as anyone who has ever ridden a bike or shared a road with a cyclist knows, most cyclists generally do an Idaho Stop if they believe it's safe. I do it, too. Knowing that I could quickly get back up to speed with the aid of the electric motor, I found myself more willing to sacrifice my forward momentum and come to a complete stop when there was a car approaching an intersection.
I have been able to find ebikes of all speeds out in the wild and after years of riding and a reflective posture for the law, I see that lawmakers were thinking less about me and my practical wants as the user, and more about the mass motor vehicle driving public, their perceptions and expectations of ‘typical bicycle speeds’ on the roads and paths. So the laws were made to bicycle NORMS, not the potential performance limits for users.
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.
There are individuals who claim to have lost considerable amounts of weight by using an electric bike. A recent prospective cohort study however found that people using e-bikes have a higher BMI. By making the biking terrain less of an issue, people who wouldn't otherwise consider biking can use the electric assistance when needed and otherwise pedal as they are able. This means people of lower fitness levels or who haven't cycled in many years can start enjoying the many health benefits E-bikes have to offer. 
While we won't be there in person, a number of vehicles will be at the show featuring the new Grin products like the GMAC Hub Motors, RH212 direct drive motors, All Axle hubs, and the Baserunner and Phaserunner_L10 controllers. If you're lucky enough to attend then check out Booth A.18 and Booth 3.12 for some velomobiles and cargo vehicles running this gear.
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.
Some argue, that an ebike should have some kind of front suspension, i.e. be able to cope with potholes at higher speed or off-road conditions. However, in countries with flat roads (e.g. Switzerland, Germany or Holland) you don't need that extra weight for extra price if you stay on roads and/or drive slowly in difficult terrain. Some makes (like the Stromer) let you choose.
Parliament has decided to approve the speed pedelec – a type of super electric bike that can reach speeds of up to 45 km/hour – for riding on cycle paths. Danish Parliament has decided that as of July 1 2018 those operating the super bikes only need to have turned 15 and wear a helmet, while the licence and number-plate demands will no longer be in play.