Each state has a law which seems "trumped" by more local ordinances (county, park etc). Also, the government designates its areas. CA state law (look up AB 1086) says that Class 1&2 e-bikes are to be treated tha same as bicycles, although as indicated above can vary by area. Almost universally (or universally) is the condition for physically challenged individuals to be able to use e-bikes in park and other off road areas. Any other states that don't comply will probably be visited by the ADA, and serves them right.