Every vehicle other than an antique vehicle displaying an antique plate operated in this State shall be equipped with a stop lamp or lamps on the rear of the vehicle which shall display a red or amber light visible from a distance of not less than 500 feet to the rear in normal sunlight and which shall be actuated upon application of the service (foot) brake, and which may but need not be incorporated with other rear lamps.

Nothing in this Section shall prohibit the use of auxiliary driving lamps, commonly referred to as "fog" lamps, when used in conjunction with head lamps, if such auxiliary driving lamps are adjusted and so aimed that the glaring rays are not projected into the eyes of drivers of oncoming vehicles.

Sec. 12‑208. Signal lamps and signal devices.
(a) Every vehicle other than an antique vehicle displaying an antique plate operated in this State shall be equipped with a stop lamp or lamps on the rear of the vehicle which shall display a red or amber light visible from a distance of not less than 500 feet to the rear in normal sunlight and which shall be actuated upon application of the service (foot) brake, and which may but need not be incorporated with other rear lamps. During times when lighted lamps are not required, an antique vehicle may be equipped with a stop lamp or lamps on the rear of such vehicle of the same type originally installed by the manufacturer as original equipment and in working order. However, at all other times, except as provided in subsection (a‑1), such antique vehicle must be equipped with stop lamps meeting the requirements of Section 12‑208 of this Act.

(625 ILCS 5/12‑212) (from Ch. 95 1/2, par. 12‑212)
Sec. 12‑212. Special restrictions on lamps. (a) No person shall drive or move any vehicle or equipment upon any highway with any lamp or device on the vehicle or equipment displaying a red light visible from directly in front of the vehicle or equipment except as otherwise provided in this Act.
(b) Subject to the restrictions of this Act, flashing lights are prohibited on motor vehicles except as a means for indicating a right or left turn as provided in Section 12‑208 or the presence of a vehicular traffic hazard requiring unusual care as expressly provided in Sections 11‑804 or 12‑215.
(c) Unless otherwise expressly authorized by this Code, all other lighting or combination of lighting on any vehicle shall be prohibited.
(Source: P.A. 86‑664.)

(d) The electric turn signal device required in Section 12‑208 of this Act must be used to indicate an intention to turn, change lanes or start from a parallel parked position but must not be flashed on one side only on a parked or disabled vehicle or flashed as a courtesy or "do pass" signal to operators of other vehicles approaching from the rear. However, such signal devices may be flashed simultaneously on both sides of a motor vehicle to indicate the presence of a vehicular traffic hazard requiring unusual care in approaching, overtaking and passing.
(Source: P.A. 78‑1297.)

(625 ILCS 5/12‑215) (from Ch. 95 1/2, par. 12‑215)
Sec. 12‑215. Oscillating, rotating or flashing lights on motor vehicles. Except as otherwise provided in this Code:
(a) The use of red or white oscillating, rotating or flashing lights, whether lighted or unlighted, is prohibited except on:
1. Law enforcement vehicles of State, Federal or
local authorities;

2. A vehicle operated by a police officer or county
coroner and designated or authorized by local authorities, in writing, as a law enforcement vehicle; however, such designation or authorization must be carried in the vehicle;

2.1. A vehicle operated by a fire chief who has
completed an emergency vehicle operation training course approved by the Office of the State Fire Marshal and designated or authorized by local authorities, in writing, as a fire department, fire protection district, or township fire department vehicle; however, the designation or authorization must be carried in the vehicle, and the lights may be visible or activated only when responding to a bona fide emergency;

3. Vehicles of local fire departments and State or
federal firefighting vehicles;

4. Vehicles which are designed and used exclusively
as ambulances or rescue vehicles; furthermore, such lights shall not be lighted except when responding to an emergency call for and while actually conveying the sick or injured;

5. Tow trucks licensed in a state that requires such
lights; furthermore, such lights shall not be lighted on any such tow truck while the tow truck is operating in the State of Illinois;

6. Vehicles of the Illinois Emergency Management
Agency, vehicles of the Illinois Department of Public Health, and vehicles of the Department of Nuclear Safety;

7. Vehicles operated by a local or county emergency
management services agency as defined in the Illinois Emergency Management Agency Act;

8. School buses operating alternately flashing head
lamps as permitted under Section 12‑805 of this Code; and

9. Vehicles that are equipped and used exclusively as
organ transplant vehicles when used in combination with blue oscillating, rotating, or flashing lights; furthermore, these lights shall be lighted only when the transportation is declared an emergency by a member of the transplant team or a representative of the organ procurement organization.