The final plat drawings and specifications of improvements shall contain a set of detailed construction and utility plans prepared by a registered professional engineer. The plans shall include typical sections, plans and profile views, construction details and estimates of quantities. All typical sections and major engineering details to be used shall be approved in advance by the Director of Public Service before completion of the plans. Prior to the granting of approval of the final plat the subdivider shall have installed the minimum required improvements, or shall have furnished a surety or certified check for the amount of the estimated construction cost of the ultimate installation and the initial maintenance of the improvements. Before the surety is accepted, it shall be approved by the proper administrative officials. The term of the surety shall extend twelve months beyond the completion date of the project. (Ord. 85-11. Passed 4-1-85.)