Interior streets shall be constructed according to City structural specifications, as delineated in the Subdivision Regulations, and properly lighted and maintained to conform to City ordinances. Their minimum paved roadway widths should ordinarily be as delineated in the Subdivision Regulations and in the Thoroughfare Plan. However, approval of interior access streets with different nonstructural dimensions will be considered by the City where the developer can demonstrate substantial compliance with the Subdivision Regulations and Thoroughfare Plan and receive approval from the City Engineer. Approval of the PD with such differences will constitute lawful approval of a waiver of the Subdivision Regulations and Thoroughfare Plan. Where streets are constructed pursuant to such a waiver, such streets shall be privately owned and maintained, and shall be constructed entirely within a public access easement. All public access easements shall be designated on the preliminary plan and the final development plan.