(a) Following the award of contract, an agreement estimate based on the contract unit prices and estimated quantities shall be prepared by the STD and submitted to the Division Administrator as soon as practicable for use in the preparation of the project agreement. The agreement estimate shall also include the actual or best estimated costs of any other items to be included in the project agreement.

(b) An agreement estimate shall be submitted by the STD for each force account project (see 23 CFR part 635, subpart B) when the plans and specifications are submitted to the Division Administrator for approval. It shall normally be based on the estimated quantities and the unit prices agreed upon in advance between the STD and the Division Administrator, whether the work is to be done by the STD or by a local public agency. Such agreed unit prices shall constitute a commitment as the basis for Federal participation in the cost of the project. The unit prices shall be based upon the estimated actual cost of performing the work but shall in no case exceed unit prices currently being obtained by competitive bidding on comparable highway construction work in the same general locality. In special cases involving unusual circumstances, the estimate may be based upon the estimated costs for labor, materials, equipment rentals, and supervision to complete the work rather than upon agreed unit prices. This paragraph shall not be applicable to agreement estimates for railroad and utility force account work.