The Law and Electric Bicycles
Extracts from 46.04 RCW (Revised Code of Washington)
"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 no more than twenty miles per hour on level ground, and incapable of further increasing the speed of the device when human power alone is used to propel the device beyond twenty miles per hour." (46.04.169 RCW)
"No driver's licence is required for operation of an electric-assisted bicycle."
"Persons under sixteen years of age may not operate an electric-assisted bicycle."
The provisions (RCW 46.16.010) relating to "a current and proper vehicle licence and display vehicle licence number plates.... shall not apply to (a) Electric-assisted bicycles."
"Persons operating electric-assisted bicycles shall comply with all laws and regulations related to the use of bicycle helmets."
"Operation of a moped or an electric-assisted bicycle on a fully controlled limited access highway or a sidewalk is unlawful."
"Electric-assisted bicycles may be operated on a multipurpose trail or bicycle lane, but local jurisdictions may restrict or otherwise limit the access of electric-assisted bicycles."
Federal law is similar to Washington state law, except it restricts power to 750 Watts.