The federal-aid highway program is the nation's most extensive and expensive continuing public works program. In 1971 alone, $4.7 billion were distributed to the states as reimbursement for highway building costs.¹ Since 1956, these federal expenditures have been funded by highway user taxes deposited into the Highway Trust Fund.² Highway trust funds are used only for building highways.

Under the federal-aid highway program, state highway departments are responsible for planning, designing, and constructing federal-aid highways. The federal government reimburses the states for a portion of the federal-aid highways' costs. The Federal Highway Administration (hereafter referred to as the FHwA) administers the federal-aid highway program.³ Its primary responsibility is to assure that the state highway departments have adhered to federal standards before the states are reimbursed for a portion of the federal-aid highways' costs. This responsibility is carried out by requiring the state highway departments to obtain federal approvals at various stages in the highway building process.