Illuminated billboards in Cook County must comply with the Illinois Highway Advertising Control Act brightness rule of 0.3 foot-candles above ambient measured at 250 feet, plus Cook County Code Ch. 38 environmental standards and Ch. 102 zoning lighting controls limiting glare and trespass onto adjacent properties.
Cook County and Illinois layer multiple lighting standards on billboards. Under 225 ILCS 440 and IDOT rules, digital and externally illuminated billboards visible from regulated highways cannot exceed 0.3 foot-candles above ambient at 250 feet. Operators must install automatic photocell dimming so brightness reduces at night. Cook County Code Ch. 38 nuisance provisions and Ch. 102 zoning add limits on light trespass onto residential parcels and require shielding of external sources. Illuminated signs must direct light onto the face, not skyward. Suburban municipalities frequently impose curfews requiring digital faces to dim or turn off between 11 p.m. and 6 a.m.
Exceeding 0.3 foot-candles, failing to install dimming photocells, or causing light trespass on adjacent residential parcels violates HACA and Cook Code Ch. 38. IDOT and county code enforcement issue notices, daily fines, and may order disconnection.
See how Des Plaines's billboard lighting rules stack up against other locations.
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