By the Federal-Aid Highway Act of 1970, Congress has enacted Section 144 of Title 23 of the United States Code, and has authorized appropriations thereby for expenditures under the Special Bridge Replacement Program to replace or reconstruct bridges when the state and the federal government determine that the bridge is of significant importance and is unsafe because of structural deficiencies, including seismic deficiencies, or physical deterioration, or functional obsolescence. The purpose of this chapter is to implement this program in this state. The boards of supervisors, city councils, the department, and the commission may do all things necessary and proper in their respective jurisdictions to secure the federal funds under the program for county highways, city streets, and state highways in accordance with the intent of the federal act and this chapter.