§ 73.02  RIDING ON BICYCLES.
   (A)   A person propelling a bicycle shall not 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 that an adult rider may carry a child securely attached to his person in a back pack or sling.
(ILCS Ch. 625, Act 5, § 11-1503)  Penalty, see § 70.99