I live in Arizona and my experience with motorized bicycle hasn't been so good so far.
I got my first motored bike because someone stole my awesome 30 speed road bike
And I felt like getting something better. So i bought an motorized bicycle from ehhh... dishonest seller for 650 dollars.
He said, "you don't need license or registration and it's bikelane legal and you can ride with the traffic because you can cruise at 40mph"
He kept telling me "it takes months for your bike to reach that speed because it's so brand new that it has to break in."
Long story short, the bike wasn't street legal because it was 66cc and it had no ability to go over 30mph because it had no expansion chamber and the stock 49cc carburetoruretor, and I needed license and registration because cops now harass people riding on motorized bicycles calling them "mopeds."
I actually ended up taking the bike to DMV and got it registered as a moped and getting a moped license. I also read through this forum and put on a new carburetoruretor, expansion chamber and a jackshaft and learned a lot about how to put together an motorized bicycle through doing tweaks and performance upgrades.
So I think i'm really ready to build my own with proper parts and not with the chinese made kit that breaks every month or two. Also now that I have a license I am planning on making this my first build comparable to a motorcycle! Wish me luck!