Yellowstone County, MT Outdoor Lighting: Billboard Lighting (2026)

A, the county's general illumination standard for signs. That standard states the light source used to illuminate any sign, including a billboard, must not be visible from any street right-of-way and must not cause glare that is hazardous or distracting to pedestrians, vehicle drivers, or adjacent properties. Externally illuminated billboards must have their light fixtures confined to the sign face itself and positioned and shielded to minimize spillover onto the surrounding area, while internally illuminated faces, including any neon lighting, must remain static in intensity and color with the light source entirely enclosed within the sign.

Flashing or rotating lights are flatly prohibited on any sign in the county, billboards included. C: every EMD must be equipped with automatic image dimming capability using ambient light monitors, this feature must stay enabled at all times, and the display must automatically adjust its brightness based on ambient light conditions rather than running at a fixed brightness after dark. Because a billboard sits closer to the interstate travel lanes than most on-premises signage, this shielding-and-dimming combination is the mechanism the joint City-County Planning Division relies on to keep nighttime billboard glare from becoming a driver-safety hazard along the Interstate Corridor and the county's commercial and industrial road frontages.