23 CFR 661.39 - How are project cost overruns funded?
(a) A request for additional IRRBP funds for cost overruns on a specific bridge project must be submitted to BIADOT and FHWA for approval. The written submission must include a justification, an explanation as to why the overrun occurred, and the amount of additional funding required with supporting cost data. If approved by FHWA, the request will be placed at the top of the appropriate queue (with a contract modification request having a higher priority than a request for additional funds for a project award) and funding may be provided if available.
(b) Project cost overruns may also be funded out of the Tribe's regular IRR Program construction funding.