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.
Last year we found a very low-priced (under $600 at Amazon) bike made by Ancheer. Overall, it made some good compromises to get down to the $600 price point but I had some issues with the build quality, the power of the motor, lack of display on the controller and size of the battery. This year a new low-cost Amazon ebike from Rattan seems to have answered many of my concerns.
The bicycle is also used for recreational purposes, such as bicycle touring, mountain biking, physical fitness, and play. Bicycle competition includes racing, BMX racing, track racing, criterium, roller racing, sportives and time trials. Major multi-stage professional events are the Giro d'Italia, the Tour de France, the Vuelta a España, the Tour de Pologne, and the Volta a Portugal.
E-bikes are zero-emissions vehicles, as they emit no combustion by-products. However, the environmental effects of electricity generation and power distribution and of manufacturing and disposing of (limited life) high storage density batteries must be taken into account. Even with these issues considered, e-bikes are claimed to have a significantly lower environmental impact than conventional automobiles, and are generally seen as environmentally desirable in an urban environment.
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.
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
Electric bicycle usage worldwide has experienced rapid growth since 1998. It is estimated that there were roughly 120 million "ebikes" on the road in China as of early 2010.. The “Electric Bikes Worldwide Reports – 2010 Update” estimates that 1,000,000 electric bicycles will be sold in Europe in 2010. The same report estimates that sales in the USA will reach roughly 300,000 in 2010, doubling the number sold in 2009.
Hmm, I think it depends on the forest. My experience has been that if you have a Class 1 ebike and are riding respectfully, most places allow it. I have a sensitive knee and carry a doctor’s note citing disability laws in Colorado and have never been approached or asked by a ranger or fellow rider about the legality of my bike. That said, I have been using the really quiet and hidden Brose motor and I ride carefully and am friendly with everyone
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. 
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.
The days when eMTBs were defined solely by the power of their motors and the size of their batteries are over. Riding performance has become the most important metric. In that pursuit, manufacturers are increasingly developing eMTBs with less power and battery capacity, which in turn handle more like regular mountain bikes. FOCUS started this movement some time ago with its Project-Y concept and later presented the FOCUS RAVEN² PRO, the first production model in a new category of bikes. However this sporty ride only convinced a handful of riders. Meanwhile, Lapierre and BULLS have both announced full-suspension trail bikes featuring the lightweight FAZUA motor for next year. It remains to be seen how many other brands will jump on board this bandwagon – but the rumour mill has already started rumbling. Moreover, it is only a matter of time before the next motor manufacturer will release its own small, lightweight motor.
Power assisted bicycles are classified in two categories in Saskatchewan. An electric assist bicycle is a 2 or 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 Canadian Motor Vehicle Safety Standards (CMVSS) 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 each. 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 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.
In the theoretical electric bike we considered up above, we had the dynamo/motor driving the back wheel directly, simply by pressing on the tire. Most electric bikes work a different way. They have compact electric motors built into the hub of the back or front wheel (or mounted in the center of the bike and connected to the pedal sprocket). Take a look at the hub of an electric bike and probably you'll see it's much fatter and bulkier than on a normal bike. You can read more about how these motors work in our main article about hub motors.