Whenever a county resolution or ordinance requires the installation of water mains, sanitary sewers, drains, or other facilities for sewers and drains, the construction of any roadways or the installation of any traffic signals or other traffic related improvements as a condition precedent to the approval of a preliminary or final subdivision or plat described in Section 5-1042, or a preliminary or final planned unit development plan and where, in the opinion of the county board such facilities, roadways or improvements may be used for the benefit of property not in the subdivision or planned unit development, and the water mains, sanitary sewers, drains or other such facilities, or such roadways or improvements are to be dedicated to the public, the county board may, by contract with the subdivider, agree to reimburse and may reimburse the subdivider for a portion of the cost of such facilities, roadways and improvements. The county board may also, by contract with the subdivider, agree to share the cost of installing required facilities. The county board may in either case recover the cost of those facilities from fees charged to owners of property not within the subdivision, or planned unit development when and as collected from such owners. Such contract shall describe the property outside the subdivision or planned unit development which may reasonably be expected to benefit from the facilities, roadways or improvements which are required to be constructed under the contract and shall specify the amount or proportion of the cost of such facilities, roadways or improvements which is to be incurred primarily for the benefit of that property. Such contract shall provide that the county shall collect such fees charged to owners of property not within the subdivision or planned unit development at any time prior to the connection to and use of the said facilities, roadways or improvements by the respective properties of each owner. Such contract may provide for the payment to the subdivider of a reasonable amount of interest on the amount expended by the subdivider in completing such facilities, roadways and improvements, with said interest to be calculated from and after the date of completion of such facilities, roadways and improvements.