(b) All bids for construction work shall be presented under sealed cover and shall be accompanied by one of the following forms of bidder’s security:

1. (1) Cash.
2. (2) A cashier’s check made payable to the county.
3. (3) A certified check made payable to the county.

4. (4) A bidder’s bond executed by an admitted surety insurer, made payable to the county.

   Upon an award to the lowest bidder, the security of an unsuccessful bidder shall be returned in a reasonable period of time, but in no event shall that security be held by the county beyond 60 days from the time the award is made.

(d) In any county that has appointed a road commissioner pursuant to Section 2006 of the Streets and Highways Code, or in any county that has abolished the office of road commissioner and complied with Section 2006.1 of the Streets and Highways Code, the board may authorize the road commissioner, or a registered civil engineer under the direction of the county director of transportation, to execute changes or additions to the work for any contract made pursuant to this article in an amount not to exceed:

1. (1) For contracts whose original cost is less than fifty thousand dollars ($50,000), the amount of the change or addition shall not exceed five thousand dollars ($5,000).
2. (2) For contracts whose original cost is fifty thousand dollars ($50,000), but less than two hundred fifty thousand dollars ($250,000), the amount of the change or addition shall not exceed 10 percent of the amount of the cost of the original contract.
3. (3) For contracts whose original cost exceeds two hundred fifty thousand dollars ($250,000), the extra cost for any change or addition to the work so ordered shall not exceed twenty-five thousand dollars ($25,000), plus 5 percent of the amount of the cost of the original contract that is in excess of two hundred fifty thousand dollars ($250,000). Notwithstanding subdivision (e), no change or addition shall exceed two hundred ten thousand dollars ($210,000).

(e) The County of Los Angeles may elect to be subject to all of the following provisions:

1. (1) For contracts whose original cost exceeds twenty-five million dollars ($25,000,000), the extra cost for any change or addition to the work so ordered shall not exceed four hundred thousand dollars ($400,000), adjusted annually to reflect the percentage change in the California Consumer Price Index.
2. (2) For contracts whose original cost exceeds fifty million dollars ($50,000,000), the extra cost for any change or addition to the work so ordered shall not exceed seven hundred fifty thousand dollars ($750,000), adjusted annually to reflect the percentage change in the California Consumer Price Index.
3. (3) If the board of supervisors delegates authority in the manner specified in subdivision (d) with regard to the contract costs specified in this subdivision, the decision by the county engineer or other county officer whom authority was delegated to shall be binding on the County of Los Angeles, and all existing protest and grievance procedures regarding that decision remain valid.
4. (4) At the time the board delegates authority in the manner specified in subdivision (d) with regard to the contract costs specified in this subdivision, the board shall implement appropriate measures to prevent fraud and ensure accountability for that delegated authority.
5. (5) This subdivision does not apply if the sum of the contracts modified under this subdivision, subdivision (c) of Section 20142, subdivision (b) of Section 20395, subdivision (b) of Section 20614, and subdivision (b) of Section 20998, exceeds seven contracts.
6. (6) If a contract is modified under this subdivision, the County of Los Angeles shall provide a review report to the Assembly Committee on Local Government and the Senate Committee on Governance and Finance no later than July 1, 2026.