Class 1 bicycles with an electric assist are equipped with only a pedal-assist motor that stops when the bicycle reaches a speed of 20 mph. Class 2 bicycles with an electric assist are equipped with a motor that can independently propel the bike without pedaling. These motors stop when the bike reaches a speed of 20 mph. Class 3 bicycles with an electric assist are equipped with a pedal-assist motor and stop when the rider stops pedaling or when the bike reaches a speed of 25 mph. These bikes are only allowed in cities with a population of one million or over.