No building, facilities, commercial establishments or service concerns may occupy or use any portion of the district until the developer provides the required on-site and off-site improvements, including (but not limited to) streets, sidewalks, sanitary and storm sewers, street lights, street trees, landscaping, screens and buffers. If necessary, a performance bond or escrow posted covering the estimated cost of said improvements shall suffice. The developer shall be required to identify the improvements, their construction cost and construction time period in a submitted development plan to the Planning and Zoning Commission. Should the developer fail to complete the improvements according to plan within the construction time period approved by the Planning and Zoning Commission, proceeds from the performance bond or escrow account shall be paid to the City of Pevely in the amount required for the improvements to be brought into conformance with the plan. If the Planned District is developed in sections, all improvements necessary for the proper functioning of the section shall be constructed and installed or a performance bond or escrow posted to the City of Pevely covering the estimated cost of the improvements.