The subdivider shall complete the improvements within one calendar year, unless an extension is granted by the city engineer. The subdivider shall complete improvements before final building inspection or the issuance of an occupancy permit for any unit in the subdivision, unless otherwise allowed by the city engineer. If the subdivider fails to complete the improvements within the specified time, the city engineer may, at his or her option, cause the uncompleted improvements to be completed and the parties executing the performance security shall be firmly bound for the payment of all necessary costs. (Ord. No. 1500, § 3 (part).)