Industrial zones.
Industrial zones. Those districts established by zoning authorities as being most appropriate for industry or manufacturing. A zone which simply permits certain industrial activities as an incident to the primary land use designation is not considered to be an industrial zone. The provisions of part 750, subpart G of this chapter relative to Outdoor Advertising Control shall apply insofar as industrial zones are concerned.
Source
23 CFR § 751.7
Scoping language
For purposes of this part, the following definitions shall apply: