Conditions on any approval may require the posting of a bond or other surety or collateral or deposit in escrow to ensure timely and adequate construction of all improvements required by this title or permit. The conditions may require a letter from a utility company or public agency legally committing it to serve the development if such service is the basis for the grant of any permit under this chapter or is otherwise required by this chapter. The developer may be required to furnish and file with the city a corporate surety bond in an amount equal to up to 110 percent of the cost of the required improvements to assure the actual construction of such improvements within a period of time required by the commission or the city planner if the permit requiring the improvements was approved by the city planner. The estimated cost of the required improvements shall be provided by a registered professional engineer retained by the developer; however, the city engineer shall review the cost estimate provided and may increase the cost estimate if the city engineer determines the estimate is low. The bond shall be approved as to form, content and amount by the city attorney. Upon satisfactory preliminary acceptance of the improvements as installed and the filing of a maintenance guarantee, the performance bond may be released. (Prior code § 16.43.806)