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. 
Around the turn of the 20th century, bicycles reduced crowding in inner-city tenements by allowing workers to commute from more spacious dwellings in the suburbs. They also reduced dependence on horses. Bicycles allowed people to travel for leisure into the country, since bicycles were three times as energy efficient as walking and three to four times as fast.
Historically, materials used in bicycles have followed a similar pattern as in aircraft, the goal being high strength and low weight. Since the late 1930s alloy steels have been used for frame and fork tubes in higher quality machines. By the 1980s aluminum welding techniques had improved to the point that aluminum tube could safely be used in place of steel. Since then aluminum alloy frames and other components have become popular due to their light weight, and most mid-range bikes are now principally aluminum alloy of some kind.[where?] More expensive bikes use carbon fibre due to its significantly lighter weight and profiling ability, allowing designers to make a bike both stiff and compliant by manipulating the lay-up. Virtually all professional racing bicycles now use carbon fibre frames, as they have the best strength to weight ratio. A typical modern carbon fiber frame can weighs less than 1 kilogram (2.2 lb).
First off we want to apologize for the longer than normal response time and email backlog as much of our team was busy both in the preparation and attendance at the Taipei Cycle Show this past week. We'll be working hard to catch up on that in the coming days and thank your patience and understanding. To all the dealers, vendors, manufacturers, component partners, and general industry friends we met at the show, what a great time and we look forward to exciting pursuits ahead.
But electric bicycles—e-bikes—are new territory for me. Broadly speaking, there are two basic options in e-bike land: power-on-demand and pedal-assist. With the former, the rider can control the speed with a throttle instead of just pedaling. Think moped but with an electric motor instead of internal combustion. Pedal-assist, by contrast, requires the rider to do some of the work. The electric motor won't engage unless the rider is pedaling.
I'm one of the hardcore cyclists at Ars, along with Jay Timmer and his new-as-of-last-fall road bike as well as copyeditor Kerry Staurseth. I love cycling, and it was a major factor in my dropping 120lb over a 12-month period starting in the summer of 2009. My daily rider/errand-runner is a 1998 Gary Fisher Marlin mountain bike. For longer rides, I use my 2009 Trek XO2 cyclecross bike. I've made a few modifications to it, including removing the bumpy cyclecross tires and swapping out the front 46-tooth chainring for a 50-tooth one. I went with a cross bike over a road bike because I'm still a Clydesdale, and I like the slightly longer wheelbase of a cross bike. I've also briefly owned a 2011 Trek Madone 5.9, which I sold not long after I bought it due to severely screwing up my right knee.
Both the Stromer and the Stoeckli are very nice looking designs and easy to handle. Reliability for both does not seem to be up to Swiss standards, e.g. some of the 2012 Stöcklis seem to have bad contacts. However, as of 2013, most of these problems should be fixed. The Cube got criticized for its battery/saddle system, but this has probably been fixed in more recent edition and it has less "punch" then the other's since the motor is smaller (324W?). I don't know about the BH Neo Nitro. Given the relatively low price of the BH Nitro, it may be the best buy in this category if you plan to cover smaller distances (the battery is limited to 9Ah, and Spain's industry does need some help ;) Anyhow, all of these models come with a variety of motors and country-specific modifications. E.g. in France, the BH Nitro comes with a 350W motor and is electronically limited to 25km/h, whereas in Switzerland you either can get a 500W - 45 km/h version or a 250W? - 25km/h version.