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.
When you have the electric motor turned on, it engages with your first push of the pedals. The difference in acceleration is startling compared to any other bike I've ridden. In Eco mode, I could sprint from 0 to 20mph in about 200 feet/65m. Switch to Turbo, and it's about 150/30m feet. As I mentioned above, you still have to pedal. The difference with an electric bike is the feeling of getting more bang for the buck. And if you want to be lazy, you can. Stay in third or fourth gear and you'll be able to stay around 18-19mph with minimal effort. But if you want to go much faster than 20mph, you'll need to work.

On October 22, 2014 PA house bill 573 passed into law, which is Act 154, which changes the definition of "pedalcycle" (bicycle) in the PA state vehicle code. "Pedalcycle" is now defined as a vehicle propelled solely by human-powered pedals or a "pedalcycle" (bicycle) with electric assist( a vehicle weighing not more than 100 pounds with two or three wheels more than 11 inches in diameter, manufactured or assembled with an electric motor rated no more than 750 watts and equipped with operational pedals and travels at speeds less than 20 mph). This bill allows the usage of pedal assisted bicycles in PA that follow the adopted state guidelines.
There is however still confusion over the various legislations involving Electric Bicycles. This stems from the fact that while places like the US and Canada offer some Federal regulation, the legality of road use is left to the various States or Provinces and then complicated further by municipal laws and restrictions. Further more there are a range of classifications and terms describing them, "Power-assisted bicycle" (Canada) or "Power assisted cycle" (United Kingdom) or ”Electric pedal assisted cycles” (European Union) or simply "electric bicycles", and as such in some cases have varying laws according to their respective classifications in some places.
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.
"Electric-assisted bicycle" means a bicycle with two or three wheels, a saddle, fully operative pedals for human propulsion, and an electric motor. The electric-assisted bicycle's electric motor must have a power output of no more than one thousand watts, be incapable of propelling the device at a speed of more than twenty miles per hour on level ground, and be incapable of further increasing the speed of the device when human power alone is used to propel the device beyond twenty miles per hour.[66]

Perhaps the cleverest thing of all about the Electric Brompton is that despite all the extra stuff, it folds up exactly the same as the non-powered variety. It's so simple, and unlike certain folding bikes we could mention, what you're left with is a genuinely small thing, rather than something that's about the size of a bike with the front wheel taken off.

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.