Colorado has cleared up their rules regarding 50cc scooters. “Threar” on Modern Buddy sums up the changes nicely in this post. While the rules still differ from most states, and the terminology is a little weird, the rules seem to give 50cc scooter riders more freedom than most states (no special license needed, very cheap registration) while closing some loopholes exploited by scofflaws and fly-by-night scooter shops. The new law also requires liability insurance, which is only fair (and by most accounts, well under $100 a year.)
The one major complaint is that 50cc scooters are limited to 40mph speed, which is under the capability of many 50cc scooters. That’s a bit of a drag, but it makes sense. That’s an arguably-reasonable speed limit for someone without a motorcycle license, and it makes it easier to weed out people cheating the system. At Amerivespa in Denver a few years ago, I remember seeing more than one Vespa GT 250 with the “2” snapped off, and many other bigger-displacement scooters with homemade “50cc” stickers. I can’t imagine police would issue citations to anyone with a motorcycle license on an insured 50cc scooter riding responsibly, unless they were REALLY speeding.