In the past, mini bikes were not street legal, and many riders - young and old alike - were heavily fined for not following the rules and sticking to tracks and private property. Now, however, fines can be avoided with mini street bikes, which are being produced more and more by mini bike manufacturers.
It all started in San Francisco, where there was a rampant disregard for local laws regarding mini bikes and the streets and highways. A local mini bike manufacturer there saw a need and filled it, producing custom built mini street bikes. Now, more manufacturers are getting up to speed on this new here-to-stay fad.
The new law in Washington set requirements for brakes and you must meet those requirements. You also have to have mirrors on both the right and left side of the handlebars. In addition, the state requires all mini street bikes to have a windshield that meets certain specifications unless the driver has goggles glasses or a face shield on when they operate the bike.
If riding on the street in unique style is what you want, call your local mini bike manufacturer and see if they are producing mini street bikes. If they aren't, ask them who is, and they will probably be able to hook you up. When making your purchase, check for the 17 digit vehicle identification number that is required for all vehicles that will be operated on public streets and highways, as well as additional safety features that are required.