Caldwell, ID Outdoor Lighting: Billboard Lighting (2026)

Caldwell folds sign lighting into its citywide Design Standards article rather than a stand-alone lighting chapter, and the rule reaches every lit sign in the city, including the sixty-foot freeway-oriented pole signs, or billboards, permitted near I-84 under § 10-02-06-8(2)(C). Section 10-02-06-12(5) opens by limiting illumination to signs where it is permitted at all, then sets operative standards: no hazardous glare toward drivers or pedestrians on a public street or private premises, full shielding of the light source whether it sits inside or outside the sign cabinet, and for externally lit signs, fixtures that keep light and glare from crossing above the horizontal plane of the sign's top edge onto the right-of-way or a neighboring property.

A separate clause not quoted above, § 10-02-06-12(5)(D), requires every electronic message center to carry a photocell so its brightness dims automatically as ambient light falls. The article's hard numeric ceiling applies to every lit sign regardless of illumination method: no sign lit at night may exceed seven hundred fifty candelas per square meter, the unit the code calls Nits. Signs sitting on freestanding monument structures near a residential neighborhood face an added restriction under Table 10-02-06-8's footnote 2: those signs must be externally illuminated only, internal illumination is off the table once the sign is adjacent to residential use or a residential zone.