The board of park commissioners of any park district in this State is authorized and empowered to establish, lay out, construct and build, within the territorial limits of the park district, elevated pleasure highways and boulevards, together with all structures, substructures, superstructures, foundations, ramps, inclines, drainage systems, lighting systems, ornamental work, curbs, gutters, safety devices, signal systems and all permanent improvements and construction work incidental thereto or connected therewith or necessary to render such elevated pleasure highways and boulevards of greatest service to the public.