As used in this article, the term:

(1) "Approach" means not more than three miles of the traffic artery on either end of the bridge and within that limit shall mean so much of the traffic arteries on either end of the bridge as shall be required to develop the maximum traffic capacity of the bridge, including necessary grading, paving, drainage structures or facilities, and other construction necessary to the approach.

(2) "Authority" means the public corporation created by the "Georgia Highway Authority Act," Ga. L. 1967, p. 385, as amended by Ga. L. 1971, p. 385, and by Ga. L. 1972, p. 826, which 1967 Act merged the public corporation known as the Georgia Rural Roads Authority created by the "Georgia Rural Roads Authority Act," Ga. L. 1955, p. 124, as amended, with the Georgia State Highway Authority, created by the "Georgia State Highway Authority Act," Ga. L. 1953, Jan.-Feb. Sess., p. 626, as amended particularly by Ga. L. 1961, p. 3, and which 1967 Act provided that all property, assets, choses in action, or other things of value of both of the constituent public corporations shall be vested in and be the property of the Georgia Highway Authority (the continuing and surviving public corporation); all the rights, powers, and duties, including their perpetual existence, previously legally granted to both constituent public corporations, shall be vested in the Georgia Highway Authority, subject, however, to all debts, obligations, liabilities, and duties incurred by the two constituent public corporations; the purpose and intention of such merger was that the Georgia Highway Authority as the successor and continuing corporation would be for the continuation of all the purposes of both constituent public corporations and would be vested with the rights, powers, duties, and obligations of both constituent public corporations, together with the additional powers and rights granted by the aforesaid "Georgia Highway Authority Act" of 1967.

(3) "Board" means the State Transportation Board or the commissioner of transportation acting as the chief executive officer of the Department of Transportation; and, whenever any action is required to be taken, any power is permitted to be exercised, any approval is to be granted, or any contract is to be executed by the State Transportation Board, pursuant to any provision of this article, the same may be taken, exercised, granted, or executed by the commissioner to the extent permitted by law.

(4) "Bonds and revenue bonds" means any bonds issued by the authority or either of the constituent public corporations, whether issued under this article or otherwise, including refunding bonds.

(5) "Bridge" means a structure, including the approaches thereto, erected in order:

(A) To afford unrestricted vehicular passage over obstructions in any public road, including but not limited to rivers, streams, ponds, lakes, bays, ravines, gullies, railroads, public highways, and canals; or (B) To afford unrestricted vehicular passage under or over existing railroads and public roads.

(6) "Cost of project or projects" means the cost of construction; the cost of all lands, properties, franchises, and rights in property; the cost of all machinery and equipment necessary for the operation of a project; financing charges; interest prior to and during construction; cost of engineering, plans and specifications, surveys, and supervision; legal expenses; expenses necessary or incident to determining the feasibility or practicability of the project; administrative expenses; fiscal expense; such other expense as may be necessary or incident to the financing authorized by this article; the expense of construction or any action permitted by this article with respect to a particular project and the placing of the same in operation; and any other expense authorized by this article to be incurred by the authority with respect to any action with regard to a particular project or projects. Any obligation or expense incurred for any of the foregoing purposes shall be regarded as a cost of the project and may be paid or reimbursed as such out of the proceeds of bonds issued under this article for such project or group of projects.

(7) "County road" means any public road or portion thereof, not located wholly within the boundaries of an incorporated municipality and not now, or as of the particular time of inquiry in the future, part of a state road or urban road as defined in paragraphs (12) and (15), respectively, of this Code section, provided that the meaning of the term "county road" shall include a public road or portion thereof on the federal-aid secondary system if such road or portion thereof is not part of the state highway system. The term shall include not only such roads as come within this definition on July 1, 1973, but also such roads, as defined in this Code section, which may from time to time be planned, laid out, and constructed by the authority pursuant to this article. The fact that a road owned by the authority and leased to the state may, as provided by this article, be declared part of the state highway system shall not destroy its identity as a county road for the purposes of this article, provided that nothing in the definition of "county road" shall in any manner alter the legal effect of said term which is intended to be synonymous with "rural road" as used in the "Georgia Highway Authority Act," Ga. L. 1967, p. 385, as amended.

(8) "Governing authority of a county" means the commissioner, board of commissioners, commission, or other person or body of persons at the time entrusted by law with the administration of the fiscal affairs of any county.

(9) "Governing authority of any incorporated municipality" means the mayor, board of aldermen, city council, board, council, commission, or other person or body of persons at the time entrusted by law with the administration of the fiscal affairs of any incorporated municipality.

(10) "Project" means:

(A) A continuous length or stretch of state road, including bridges thereon, as to which the authority has undertaken or agreed to undertake any action permitted by the terms of this article or as to which any such action has been completed by the authority;

(B) A continuous length or stretch of county road, including bridges thereon, as to which the authority has undertaken or agreed to undertake any action permitted by the terms of this article or as to which any such action has been completed by the authority;

(C) A continuous length or stretch of urban road, including bridges thereon, as to which the authority has undertaken or agreed to undertake any action permitted by the terms of this article or as to which any such action has been completed by the authority; and

(D) One or more bridges, as defined in paragraph (5) of this Code section, together with the approaches thereto, as defined in paragraph (1) of this Code section.

(11) "Self-liquidating" means a project or group of projects whose revenues, rents, and earnings derived by the authority therefrom will be sufficient to pay, in the judgment of the authority, the principal of and interest on bonds which may be issued for the cost of such project or group of projects and to pay the cost of maintaining, repairing, and operating the projects or combination of projects and other lawful expenses of the authority.

(12) "State road" means any public road or portion thereof which is part of the state highway system, The Dwight D. Eisenhower System of Interstate and Defense Highways, the federal-aid primary system, the federal-aid secondary system, or the Appalachian Development Highway System, together with the local access roads appertaining thereto, in the manner provided by law.

(13) "Urban county" means any county with a population of more than 50,000 according to the most recent official United States census.

(14) "Urban incorporated municipality" means a municipal corporation incorporated and chartered pursuant to an Act of the General Assembly and which has a population of 5,000 or more according to the most recent official United States census.

(15) "Urban road" means any public road or portion thereof located:

(A) Anywhere wholly within the boundaries of an urban county; or

(B) Wholly or partly within an urban incorporated municipality within the boundaries of a county with a population under 50,000 according to the most recent official United States census and extending no more than two miles outside of such urban incorporated municipality.

The term shall include not only such roads as come within this definition on or after July 1, 1973, but also such roads as defined in this Code section which may from time to time be planned, laid out, and constructed by the authority pursuant to this article. The fact that a road owned by the authority and leased to the state may be declared part of the state highway system, as provided by this article, shall not destroy its identity as an urban road for the purposes of this article.