About 25 states have passed the model law pushed by People for Bikes, which represents the bike industry. Here's the info on each state.
E-bike laws
It's based on the three class system, Class 1 pedal assist to 20 MPH, class 2 throttle to 20 MPH, class 3 pedal assist to 28 MPH.
I'm really trying to find out if any cities are banning e-bikes from greenways or MUPs. I haven't found any yet. A few that had bans like Seattle, have changed their rules.