Perhaps the minority because "bikes" faster than Class 3 (28 mph, PAS-only) are classified as mopeds/motorcycles (depending on factors that I haven't studied) and require license & insurance. Problem in certain litigious areas (like Orange County, CA where I reside) is if one has an accident and isn't covered, it could be very expensive. FME, now, the police seem to ignore bikes as long as the rider is "pedaling".