As used in sections 13b-31c to 13b-31e, inclusive, “scenic road” means any state highway or portion thereof that (1) passes through agricultural land or abuts land on which is located an historic building or structure listed on the National Register of Historic Places or the state register of historic places, compiled pursuant to section 10-409, or (2) affords vistas of marshes, shoreline, forests with mature trees or notable geologic or other natural features.