No buildings, facilities, establishments or service concerns may occupy or use any portion of the "PDA" until the required related off-site improvements, including, but not limited to, streets, sidewalks, sanitary and storm sewers, street lights and street trees are constructed or a performance bond or escrow, as determined by the Planning and Zoning Commission, are posted covering the construction cost. If the "PDA" is to be developed in sections, all improvements necessary to the proper operations and functioning of the section, even though the same may be located outside the section, must be constructed and installed or a performance bond or escrow posted, as determined by the Planning and Zoning Commission covering the estimated improvements cost.