Under Title 23, Chapter 316 of the code, bicycles and motorized bicycles are defined as follows: Bicycle—Every vehicle propelled solely by human power, and every motorized bicycle propelled by a combination of human power and an electric helper motor capable of propelling the vehicle at a speed of not more than 20 miles per hour on level ground upon which any person may ride, having two tandem wheels, and including any device generally recognized as a bicycle though equipped with two front or two rear wheels. The term does not include such a vehicle with a seat height of no more than 25 inches from the ground when the seat is adjusted to its highest position or a scooter or similar device. No person under the age of 16 may operate or ride upon a motorized bicycle. Motorized Scooter—Any vehicle not having a seat or saddle for the use of the rider, designed to travel on not more than three wheels, and not capable of propelling the vehicle at a speed greater than 30 miles per hour on level ground.[90]
Federal law defines the limits of a low speed electric bike, equating it to a bicycle, and bypassing the definition of a motor vehicle only “For purposes of motor vehicle safety standards…” which means that the manufacturers of these bicycles don’t have to meet federal equipment requirements, and are instead governed by the manufacturing requirements of the Consumer Product Safety Act. There is no mention of exemption from other federal, state, and local traffic laws, or exemption from the definition of a motor vehicle for other purposes.3 This means the law applies to the manufacturer’s product and sale, avoiding federal safety requirements applying to a motor vehicle such as brake lights, turn signals and braking specifications. The goal of the law was to give businesses a legal framework to define and sell low speed electric bikes without the more stringent Federal classification of a motor vehicle. Ebikes that meet the criteria are considered a “bicycle”, do not meet the definition of a motor vehicle, and will be regulated by the Consumer Product Safety Commission. The law also grants the commission authority to add safety requirements to this product. The Federal law supersedes all state laws that equate bicycles to ebikes where the state law is more stringent (lower limits) on power and speed.
Controllers for brushless motors: E-bikes require high initial torque and therefore models that use brushless motors typically have Hall sensor commutation for speed and angle measurement. An electronic controller provides assistance as a function of the sensor inputs, the vehicle speed and the required force. The controllers generally allow input by means of potentiometer or Hall Effect twist grip (or thumb-operated lever throttle), closed-loop speed control for precise speed regulation, protection logic for over-voltage, over-current and thermal protection. Bikes with a pedal assist function typically have a disc on the crank shaft featuring a ring of magnets coupled with a Hall sensor giving rise to a series of pulses, the frequency of which is proportional to pedaling speed. The controller uses pulse width modulation to regulate the power to the motor. Sometimes support is provided for regenerative braking but infrequent braking and the low mass of bicycles limits recovered energy. An implementation is described in an application note for a 200 W, 24 V Brushless DC (BLDC) motor.[43]

"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]

Electric mountain bikes have garnered a lot of attention for their ability to help riders go higher, further, and faster on the trail. As a result, there have been some impressive new eMTB models to hit the market in recent years, making it easier than ever to head off-road. Our favorite is the Haibike SDURO HardNine, which comes equipped with a 350-watt Bosch Performance CX drive and a 500 watt-hour battery. This gives it a range of up to 70 miles, along with a top speed of 20 mph, which is plenty fast on singletrack.


Controllers for brushless motors: E-bikes require high initial torque and therefore models that use brushless motors typically have Hall sensor commutation for speed and angle measurement. An electronic controller provides assistance as a function of the sensor inputs, the vehicle speed and the required force. The controllers generally allow input by means of potentiometer or Hall Effect twist grip (or thumb-operated lever throttle), closed-loop speed control for precise speed regulation, protection logic for over-voltage, over-current and thermal protection. Bikes with a pedal assist function typically have a disc on the crank shaft featuring a ring of magnets coupled with a Hall sensor giving rise to a series of pulses, the frequency of which is proportional to pedaling speed. The controller uses pulse width modulation to regulate the power to the motor. Sometimes support is provided for regenerative braking but infrequent braking and the low mass of bicycles limits recovered energy. An implementation is described in an application note for a 200 W, 24 V Brushless DC (BLDC) motor.[43]
Speaking of which, if you're used to non-electric cycles, be aware that e-bikes are heavy and capped at 25kph or 15.5mph. In many cases, that means the bike starts to feel like its actively fighting against you, if you try to push the speed higher than that by pedalling. That's especially true with heavier bikes, for obvious reasons, and can take a while to get used to. 
The federal Consumer Product Safety Act defines a "low speed electric bicycle" as a two or three wheeled vehicle with fully operable pedals, a top speed when powered solely by the motor under 20 mph (32 km/h) and an electric motor that produces less than 750 W (1.01 hp). The Act authorizes the Consumer Product Safety Commission to protect people who ride low-speed electric vehicles by issuing necessary safety regulations.[63] The rules for e-bikes on public roads, sidewalks, and pathways are under state jurisdiction, and vary.
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