The Advisory Agency may, as a condition of approval of a tentative parcel map, impose a requirement that any onsite or offsite improvements be constructed within a specified time period following recordation of the parcel map and prior to issuance of a permit or other grant of approval for the development of a parcel upon a finding that the fulfillment of the construction requirements is a necessary prerequisite to the orderly development of the surrounding area. An improvement agreement shall be executed and improvement security shall be posted prior to approval of the final parcel map. (Ord. 5329 § 6; August 25, 1992.)