The Footloose has no chain, however -- it's entirely electrically driven. It takes very little effort to get to your destination, meaning you arrive at work without having broken a sweat. The downside is that when you run out of power, you're not going anywhere. And pedalling from a standstill, waiting for the motor to kick in, is an odd sensation that takes some getting used to.
Great question… a real world situation from someone doing their best to follow the law but also be realistic about time/distance. What follows is my opinion on the matter based on lots of electric bike riding experience, this is not legal advice. You can probably ride with electric assist across the dirt way with no issues and avoid any negative response that might arise as long as you’re polite to other cyclists and pedestrians and pedal along without going too fast. If someone called you out about it you could easily hop off, walk your bike and explain that you use the assist to help make your commute possible or possibly, like me, you have a knee injury and it’s difficult to pedal through softer terrain like gravel. Another different approach might be to shut the bike off completely before entering the gravel section, you could even take the battery off and put it in a backpack or as mentioned earlier… just walk the bike. Imagine if you had a motorized dirt bike and were just pushing it along a sidewalk… this kind of vehicle definitely is not allowed on sidewalks or most gravel paths like the one you’re describing but if you were escorting it carefully, you’d be honoring the spirit of the law and if an officer or pedestrian jumped out and started questioning you about your “motorized vehicle” it is my feeling that a genuine explanation and apology or request for guidance would go very well. I personally have never had issues riding electric bikes in part because I am thoughtful about how I use them. I do occasionally switch them off and sometimes I get off and walk. I have asked police in many cities across the US what they thought about ebikes and in every case I have received positive interest and support with guidance to ride safe with a helmet and follow traffic laws in the street. I hope this helps and I wish you well, it’s nice that you care enough to ask and I hope you’re treated well by others out on the road. The flip side of this response is that I have been harassed, yelled at and even swerved at by automobiles when riding bicycles and electric bikes. This usually happens in the evening after work lets out when traffic is heavy and I’m riding on the shoulder or in the street (where marked to do so) and I believe it has to do with territory, testosterone and socio-economic standing more so than laws or anything like that.
There's no question that electric bikes are far better for the environment than petrol-powered car engines. But that doesn't mean they're completely perfect. Making and disposing of batteries can be very polluting. Not only that, but an electric bicycle is still using energy that has to come from somewhere. You may think you're using clean green power, but the electricity you use for getting about might have come from a filthy old, coal-fired power plant or one driven by nuclear energy. (If you're lucky, of course, it might have come from solar panels or a wind turbine!) Electric bikes are nowhere near as environmentally friendly as ordinary push bikes, but nothing is ever perfect—and, as people often say, "the perfect is the enemy of the good." Electric bikes are certainly a step in the right direction. If everyone used them to get about instead of cars, global warming might be less of a problem, and the world would be a far cleaner and healthier place!
Some US companies, notably in the tech sector, are developing both innovative cycle designs and cycle-friendliness in the workplace. Foursquare, whose CEO Dennis Crowley "pedaled to pitch meetings ... [when he] was raising money from venture capitalists" on a two-wheeler, chose a new location for its New York headquarters "based on where biking would be easy". Parking in the office was also integral to HQ planning. Mitchell Moss, who runs the Rudin Center for Transportation Policy & Management at New York University, said in 2012: "Biking has become the mode of choice for the educated high tech worker".
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.
When last checked, no E-bikes satisfied this requirement, so ebikes cannot be registered in New Jersey. However, NJ Bill A2581, introduced March 22, 2010, would permit the use of low-speed electric bicycles upon the roadways and bicycle paths in NJ, where a low-speed electric bicycle is defined as a two-wheeled vehicle with fully operable pedals for human propulsion and an electric motor of less than 100 pounds and 750 watts, whose maximum speed on a paved level surface is less than 20 miles per hour. The bill has been referred to the state's Assembly Transportation, Public Works and Independent Authorities Committee.
Electric powered bicycles slower than 20 km/h without pedaling are legally recognized as a non-mechanically operated vehicle in China. According to "TECHNOLOGY WATCH", this should help promote its widespread use. Electric bicycles were banned in some areas of Beijing from August 2002 to January 2006 due to concerns over environmental, safety and city image issues. Beijing has re-allowed use of approved electric bicycles as of January 4, 2006. Some cities in China still ban electric bikes.
Saddles also vary with rider preference, from the cushioned ones favored by short-distance riders to narrower saddles which allow more room for leg swings. Comfort depends on riding position. With comfort bikes and hybrids, cyclists sit high over the seat, their weight directed down onto the saddle, such that a wider and more cushioned saddle is preferable. For racing bikes where the rider is bent over, weight is more evenly distributed between the handlebars and saddle, the hips are flexed, and a narrower and harder saddle is more efficient. Differing saddle designs exist for male and female cyclists, accommodating the genders' differing anatomies and sit bone width measurements, although bikes typically are sold with saddles most appropriate for men. Suspension seat posts and seat springs provide comfort by absorbing shock but can add to the overall weight of the bicycle.
UPDATE (2019-03-15): I've now got more than 110 miles on the bike and still loving it. The longest ride I did was 28.5 miles and the display was still showing about two bars left on the battery. But the battery gauge is not accurate. Even when it went down to two bars it would also jump back up to 4 bars and stay that way for awhile. So it's really hard to tell how much power you have left. On one ride, after 14 miles the pedal assist stopped working all of a sudden. I stopped and re-seated the cadence sensor and it started working again. Even when PAS didn't work the throttle was still working. It hasn't happened since. There was also a lot of rattling noises which I found was the battery rattling around in the mounting bracket.
The Bosch Performance CX is still one of the most popular motors on the market. It’s synonymous with reliability, but it’s getting on in years. The newly presented Active Line looks like a glimpse into Bosch’s future: it is more compact, lighter, has less internal resistance, and uses a large chainring. It can only be a matter of time before Bosch releases a new performance motor.
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. 
The two most common types of hub motors used in electric bicycles are brushed and brushless. Many configurations are available, varying in cost and complexity; direct-drive and geared motor units are both used. An electric power-assist system may be added to almost any pedal cycle using chain drive, belt drive, hub motors or friction drive. BLDC hub motors are a common modern design. The motor is built into the wheel hub itself, and the stator fixed solidly to the axle, and the magnets attached to and rotating with the wheel. The bicycle wheel hub is the motor. The power levels of motors used are influenced by available legal categories and are often, but not always limited to under 750 watts.
Across Europe, where e-bikes were embraced by the public long before the rest of the world, e-bike growth has averaged in excess of 20 percent each year between 2014 and 2017, with a whopping 25.3 percent growth to a total of two million e-bike sales in 2017. Analysts predict that strong growth will continue, with worldwide e-bike sales expected to hit $23.83 billion by 2025. A lot of that growth will be right here in the US.
E-bikes are typically offered in 24V, 36V and 48V configurations. Higher voltage generally means higher top speed – but that may not always be the case. Since the efficiency of a motor and drive system can have an effect on power and speed, a 24V setup could have the same top speed as a 36V setup. Generally you can expect 15-18 mph on a 24v setup, 16-20 mph on a 36V setup and 24-28 mph on a 48V setup. Although it far exceeds Federal laws, some conversion kits can even be run at 72V for speeds of 35+ mph! However, this puts significant stress on bicycle components. Consider that even the fastest athletes only travel 17-18 mph on a conventional bicycle, so 20 mph feels very fast to most riders. Anything over this speed can be unsafe and exceeds law regulations.
Louisiana Revised Statute R.S. 32:1(41) defines a motorized bicycle as a pedal bicycle which may be propelled by human power or helper motor, or by both, with a motor rated no more than one and one-half brake horsepower, a cylinder capacity not exceeding fifty cubic centimeters, an automatic transmission, and which produces a maximum design speed of no more than twenty-five miles per hour on a flat surface. Motorized bicycles falling within this definition must be registered and titled under Louisiana law. Additionally, a motorized bicycle operated upon Louisiana roadways or highways by a person fifteen years of age or older and producing more than five horsepower must possess a valid driver's license with a motorcycle endorsement and adhere to laws governing the operation of a motorcycle, including the wearing of approved eye protectors or a windshield and the wearing of a helmet. The statute also states that "Motorized bicycles such as pocket bikes and scooters that do not meet the requirements of this policy shall not be registered."
In some countries mixed systems, i.e. pedaling and/or using a throttle is legal. In EU countries and Switzerland this is not the case. I.e. you can buy an electric scooter, but this is not considered to be an e-bike in the moped / light scooter category. That kind of hack is probably more difficult, unless the original design has been modified to fit with (s)Pedelec specs. E.g. The Ezee models are of that kind and modifications to revert to the original does not seem to be too difficult...
The U.S. Consumer Product Safety Act states that electric bicycles and tricycles meeting the definition of low-speed electric bicycles will be considered consumer products. The Consumer Product Safety Commission (CPSC) has regulatory authority to assure, through guidelines and standards, that the public will be protected from unreasonable risks of injury or death associated with the use of electric bicycles.
To operate the bike, you have to pedal for a second or so before the thumb throttle becomes active. This is often a cost and energy-saving measure designed into electric bicycles and scooters. Being able to start the motor from rest requires extra sensors and higher battery power. Starting the motor while it is in motion removes the need to install extra sensors in the motor (and thus removes one more possible failure or maintenance issue) and also eeks more range out of the battery by putting the energy intensive initial startup responsibility solely on the rider.
E-Bikes are the perfect way to ride across any city: stress-free, easy and fast travel, fun exercise, riding in style and ability to carry heavier loads than a normal bike. Practicing what we preach, this Valentine’s Volt partnered with leading London florist Rebel Rebel to deliver flowers all across London. Every hour on the hour 1 lucky person received a beautiful bouquet for free, just because we wanted to share the love!
The rest of the bike is equally impressive. Integrated lights in the front and the rear run directly off the main battery, so you’re never replacing coin cells or AAA batteries. And the disc brakes give you plenty of stopping power. The 36-volt battery attaches to the down tube and is designed to be easily removed for recharging. A key-lock at the top of the mount ensures that no one can steal your battery if your bike is left in a public place. And a built-in alarm system, activated with a car-like key fob, is ear-splitting enough to keep thieves away altogether. (Miller promises the alarm’s sensitivity is tuned so it shouldn’t go off if the bike is jostled at a public bike rack, but I didn’t have the bike long enough to test this out.)
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.
I discovered these downsides when, on my third day with the bike, I got a flat tire and had to carry it onto the subway with me for those last few miles back to my apartment. The cause of the flat is unknown; the bike mechanic who eventually fixed it didn’t see anything wrong with the rims. But the experience of trying to maneuver an almost 40 pound e-bike on and off a crowded subway car during rush-hour is not one I can recommend.
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.
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.
Built around a heavy-duty alloy frame, the GSD eschews many of the traits of other cargo bikes: long wheelbases, bigger wheels, and especially, an unwieldy ride. Yet it boasts an extensive capacity, nimble handling—even fully loaded, thanks to a short wheelbase and 20-inch wheels—and enduring range in a package not much bigger than most non-cargo e-bikes. The stout frame holds a 250-watt Bosch motor that gives up to 275 percent of your power back to the pedals and reaches 20 mph. The GSD has room for two battery packs, extending the batteries’ combined range to a claimed 150 miles and making the Tern one of the longest-lasting e-bikes on the market. A laundry list of accessories and a (claimed) 396-pound carrying capacity round out the GSD’s status as an epic day-tripper.
Seth Miller said he founded the company after his first electric bike was stolen from where it was parked in front of the midtown office building where he worked. The company that manufactured the bike had disbanded, so he started researching different suppliers. He soon discovered that a majority of the e-bikes sold in the US are just cobbled together from a variety of off-the-shelf Chinese-made parts found in a catalog. It sounded simple, so Miller figured he’d try it himself.
Haibike ships the HardNine with 29-inch tires, 180-millimeter hydraulic disc brakes, a 100-millimeter front suspension fork, and a nine-speed Shimano shifting system. The bike’s LCD readout is affixed to the handlebars and displays the current speed, level of charge, remaining range, and current pedal assist mode. The company says the battery can be completely recharged in just four hours, minimizing downtime between rides.