Oversize and/or off-site extensions of utilities, pavements and other improvements shall be designed and constructed to facilitate the orderly development of nearby land which is an integral part of the neighborhood service or drainage area. Where the City Engineer determines that improvements in excess of the size needed to serve the proposed subdivision are necessary, the subdivider shall install all improvements required to serve his subdivision plus the additional oversize and/or off-site improvements required. The subdivider may contract with adjacent property owners and/or subdividers of adjacent land for reimbursement of the oversize and/or off-site improvements required. Such improvements shall be available for connections by individual property owners and/or subdividers of adjoining land.