§ 74.03 MANNER AND NUMBER RIDING.
   (A)   It is unlawful for any person propelling a bicycle to ride other than upon or astride a permanent and regular seat attached thereto.
   (B)   No bicycle, including a tandem bicycle, cargo or utility bicycle or trailer, shall be used to carry more persons at one time than the number for which it is designed and equipped, except on a baby seat attached to the bicycle, provided that the seat is equipped with a harness to hold the child securely in the seat and that protection is provided against the child's feet hitting the spokes of the wheel, or in a seat attached to the bicycle operator.
Penalty, see § 74.99