Modifies provisions relating to outdoor advertising

The provided context does not include specific details about SB 291's provisions, modifications, or affected parties. The official abstract only states it "modifies provisions relating to outdoor advertising" without describing the actual changes. Without further information on the specific rules or mechanisms being altered (e.g., signage regulations, zoning, or permit processes), a substantive summary cannot be created. More detailed bill text or amendments would be needed to fulfill this request.