Advertising systems are those forms of advertising in which the advertising medium is visible from public traffic. According to the Hessian Building Code (HBO), advertising systems are considered structural installations. The installation of advertising systems is usually subject to building permits. If the advertising systems are installed near heavily frequented roads, the responsible road construction authorities are usually involved because of the safety and ease of traffic.

Advertising installations with a viewing area of up to 1 m² or within the scope of municipal statutes do not require a building permit if the municipalities have made stipulations on advertising installations and these stipulations are complied with by the advertising installations.