Illinois Code § 15

§ 15.

Outdoor lighting control. All new luminaires purchased with State funds after the effective date of this Act or installed after the effective date of this Act on a structure or land that is owned and managed by the Department of Natural Resources, including roadways, facilities, properties, nonhabitable structures, monuments, and public right-of-way spaces, including sidewalks, with the intended purpose of outdoor illumination must follow the following outdoor lighting control requirements: (1) Permanent outdoor luminaires must be fully shielded with an IES BUG rating and produce less than 1% of its emitted light above 80 degrees from the downward vertical direction of nadir. Light should not be emitted at an angle above 60 degrees from the downward vertical direction of nadir. (2) Luminaires must avoid light trespass by not exceeding an illuminance of one lux as measured at ground level both horizontally and vertically at the property boundary. (3) Luminaires must have a correlated color temperature less than or equal to 2,700 Kelvin. In residential areas, dark sky locations, or environmentally sensitive areas, such as State parks and outdoor recreation facilities, correlated color temperature should be no more than 2,200 Kelvin. (4) Outdoor lighting must be minimized to no more than 25% above ANSI/IES standards or United States Department of Transportation recommendations. (5) Facade lighting must be minimized to no more than 25% above ANSI/IES standards, must project downward, and must not violate the light trespass limits in paragraph (2). (6) When the installation or replacement of roadway lighting is planned, the appropriate authority must determine whether reflective roadway markings or reflective signage is appropriate and safe for the situation in lieu of outdoor lighting. Reflectorized roadway markings, lines, warning signs, informational signs or other passive means must be used for roadway lighting, except at intersections of 2 or more streets or highways, unless it is determined that adequate safety cannot be achieved by reflective means. (7) No artificial lighting above one lux, as measured at ground level both horizontally and vertically, may trespass onto land or waterways designated or managed as habitat, reserve, natural area, open space, or wilderness. (Source: P.A. 103-1007, eff. 1-1-25.)