these statutes are current as of this month.
340.01(29m)(am)
(am) "Moped" means any of the following motor vehicles capable of speeds of not more than 30 miles per hour with a 150-pound rider on a dry, level, hard surface with no wind, excluding a tractor, a power source as an integral part of the vehicle and a seat for the operator:
340.01(29m)(am)1.
1. A bicycle-type vehicle with fully operative pedals for propulsion by human power and an engine certified by the manufacturer at not more than 130 cubic centimeters or an equivalent power unit.
340.01(29m)(am)2.
2. A Type 1 motorcycle with an automatic transmission and an engine certified by the manufacturer at not more than 50 cubic centimeters or an equivalent power unit.
340.01(29m)(bm)
(bm) "Moped" does not include a motor bicycle.
340.01(30)
(30) "Motor bicycle" means any of the following:
340.01(30)(a)
(a) A bicycle to which a power unit not an integral part of the vehicle has been added to permit the vehicle to travel at a speed of not more than 30 miles per hour with a 150-pound rider on a dry, level, hard surface with no wind and having a seat for the operator.
340.01(30)(b)
(b) A 2-wheeled or 3-wheeled vehicle that has fully operative pedals for propulsion by human power and an electric motor of less than 750 watts and that is capable, when powered solely by the motor, of a maximum speed of less than 20 miles per hour with a 170-pound rider on a dry, level, hard surface with no wind
registration exemption
341.05 When vehicles exempt from registration. A
vehicle, even though operated upon a highway of this state, is
exempt from registration if any of the following applies
(23) The vehicle is a motor bicycle or bicycle, except as provided in s. 349.18.
rights of towns and citys on motor assisted bicycle laws
349.18 Additional traffic-control authority of counties and municipalities.
(1)Any city, village or town, by ordinance, may:
(a) Designate the number of persons that may ride on a motor bicycle at any one time and the highways upon which a motor bicycle or moped may or may not be operated.
(2)Any city, town or village may by ordinance enacted pursuant to s. 349.06 regulate the operation of bicycles and motor bicycles and may by ordinance require registration of any bicycle or motor bicycle owned by a resident of the city, town or village, including the payment of a registration fee.
(3)Any county, by ordinance, may require the registration of any bicycle or motor bicycle owned by a resident of the county if the bicycle or motor bicycle is not subject to registration under sub. (2). Such ordinance does not apply to any bicycle or motor bicycle subject to registration under sub. (2), even if the effective date of the ordinance under sub. (2) is later than the effective date of the county ordinance. A county may charge a fee for the registration.
History: 1977 c. 116, 288; 1983 a. 243, 288, 343, 538; 1985 a. 135, 197, 298, 332; 1989 a. 167; 1993 a. 246; 1995 a. 138; 1997 a. 27.
Cities and villages cannot license bicyclists, create bicycle courts, or impound bicycles in the absence of express legislative authorization. 66 Atty. Gen. 99.
*rules of the road
346.16 Use of controlled-access highways, expressways and freeways.
(2)
(a) Except as provided in par. (b), no pedestrian or person riding a bicycle or other nonmotorized vehicle and no person operating a moped or motor bicycle may go upon any expressway or freeway when official signs have been erected prohibiting such person from using the expressway or freeway.
*rules at stop lights
346.37 Traffic-control signal legend.
4. Notwithstanding subd. 1., a motorcycle, moped, motor bicycle, or bicycle facing a red signal at an intersection may, after stopping as required under subd. 1. for not less than 45 seconds, proceed cautiously through the intersection before the signal turns green if no other vehicles are present at the intersection to actuate the signal and the operator of the motorcycle, moped, motor bicycle, or bicycle reasonably believes the signal is vehicle actuated. The operator of a motorcycle, moped, motor bicycle, or bicycle proceeding through a red signal under this subdivision shall yield the right-of-way to any vehicular traffic, pedestrian, bicyclist, or rider of an electric personal assistive mobility device proceeding through a green signal at the intersection or lawfully within a crosswalk or using the intersection. This subdivision does not affect any authorization for a bicyclist under subd. 2.
*special rules for bicycles
346.79 Special rules applicable to bicycles
(1)A person propelling a bicycle shall not ride other than upon or astride a permanent and regular seat attached thereto.
(2)
(a) Except as provided in par. (b), no bicycle may be used to carry or transport more persons at one time than the number for which it is designed.
(b) In addition to the operator, a bicycle otherwise designed to carry only the operator may be used to carry or transport a child seated in an auxiliary child's seat or trailer designed for attachment to a bicycle if the seat or trailer is securely attached to the bicycle according to the directions of the manufacturer of the seat or trailer.
(3)No person operating a bicycle shall carry any package, bundle or article which prevents the operator from keeping at least one hand upon the handle bars.
(4)No person riding a bicycle shall attach himself or herself or his or her bicycle to any vehicle upon a roadway.
(5)No person may ride a moped or motor bicycle with the power unit in operation upon a bicycle way.
Nice cops, who knew? 
