§ 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 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