Here in my home state of Utah, side-by-sides are street legal. Well, sorta. You aren't just allowed to rock up to a powersport dealership, drop $30,000, and drive off. You have to do a few things to them before you can apply for registration with the DMV, i.e. install turn signals, make sure the lights are to code, and, well, that's about it.
Listen, I didn't say it was difficult.
But Utah, along with a host of other states, has recently seen the rise in UTV ownership—a story on the reasoning why is something I'm working on for a later date—and have begun allowing these mini-trophy trucks and utility vehicles out on the road like any other normal car. States across the country have adopted similar laws, letting the two intermingle on local roads. Highways are still not allowed, but who knows if that'll change.