In unincorporated Cook County, digital billboards along expressways and primary highways must comply with Cook County Zoning Ord. Ch. 102 sign standards plus the Illinois Highway Advertising Control Act (225 ILCS 440), which caps brightness, mandates eight-second message holds, and prohibits animation, flashing, or scrolling effects.
Outdoor advertising along Illinois interstates and federal-aid primary highways is dual-regulated. The Illinois Highway Advertising Control Act (225 ILCS 440) requires an IDOT permit for any sign over 32 square feet visible from a regulated highway, mandates 500-foot spacing in urban areas, and limits digital faces to static messages held at least eight seconds with transitions under two seconds. Brightness cannot exceed 0.3 foot-candles above ambient at 250 feet. Cook County Zoning Ch. 102 restricts digital billboards to industrial and certain B-3 districts, requiring special use permits. Most suburban municipalities apply stricter sign codes limiting static-to-digital conversions.
Operating an unpermitted digital billboard, exceeding brightness limits, or running animated or flashing content violates 225 ILCS 440 and Cook Zoning Ch. 102. IDOT can order removal at the owner's expense and assess civil penalties; counties add daily zoning fines.
See how Des Plaines's digital billboards rules stack up against other locations.
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