(a) On-the-job special training provisions. State highway agencies will be reimbursed on the same pro-rata basis as the construction costs of the Federal-aid project.

(b) Supportive services.

(1) The State highway agency must keep a separate account of supportive services funds since they cannot be interchanged with regular Federal-aid funds. In addition, these funds may not be expended in a manner that would provide for duplicate payment of Federal or Federal-aid funds for the same service.

(2) Where a State highway agency does not obligate all its funds within the time specified in the particular year's allocation directive, the funds shall revert to the FHWA Headquarters Office to be made available for use by other State highway agencies, taking into consideration each State's need for and ability to use such funds.