(A) Any person operating a bicycle or motorized pedalcycle upon a roadway at less than the normal speed of traffic at the time and place and under the conditions then existing shall ride as close as practicable to the right-hand curb or edge of the roadway except under the following situations:
(1) When overtaking and passing another bicycle, motorized pedalcycle, or vehicle proceeding in the same direction; or
(2) When preparing for a left turn at an intersection or into a private road or driveway; or
(3) When reasonably necessary to avoid conditions including, but not limited to, fixed or moving objects, parked or moving vehicles, bicycles, motorized pedalcycles, pedestrians, animals, surface hazards, or substandard width lanes that make it unsafe to continue along the right- hand curb or edge. For purposes of this division (A)(3), a SUBSTANDARD WIDTH LANE means a lane that is too narrow for a bicycle or motorized pedalcycle and a vehicle to travel safely side by side within the lane; or
(4) When approaching a place where a right turn is authorized.
(B) Any person operating a bicycle or motorized pedalcycle upon a one-way highway with two or more marked traffic lanes may ride as near the left-hand curb or edge of the roadway as practicable.
(ILCS Ch. 625, Act 5, § 11-1505)
(C) Persons riding bicycles or motorized pedalcycles upon a roadway shall not ride more than two abreast, except on paths or parts of roadways set aside for their exclusive use. Persons riding two abreast shall not impede the normal and reasonable movement of traffic and, on a laned roadway, shall ride within a single lane subject to the provisions of divisions (A) and (B) above. (ILCS Ch. 625, Act 5, § 11-1505.1)
Penalty, see § 70.99