(a) The costs of the grade crossing elimination project in which the railroad or railroads shall be required to share shall include the costs of surveys, preparation of plans and specifications, the securing of estimates or bids, if any, and the total cost of construction of the grade separation structures involved, including the establishment of drainage and any excavation and other expenses involved in constructing public roadways or railroad lines under any grade separation structure. However, the railroad or railroads shall not be required to participate in the cost of any construction outside the limits of grade or alignment change required for the public road to go over or under the track or tracks of the railroad or railroads nor in any costs apportionable to purposes other than the elimination of the grade crossing. Where additional lanes are added to the public road, the railroad's share of the cost, if any, shall be based on the cost of a grade elimination project having the same number of lanes as the public road prior to the construction of said grade elimination project.

(b)(1) The costs of the project shall be shared by the parties involved in such manner as may be agreed upon by the railroad or railroads involved and the department, county, or municipality. Such agreement shall have precedence over any existing agreement on the same subject matter and shall give consideration to the following factors: the benefits accruing to the railroad or railroads and to the public, respectively, from the elimination of the grade crossing; the circumstances under which the grade crossing was created; any preexisting rights of the railroad or railroads as result of being first in position; comparison of the degree of danger caused by the railroad or railroads and by quantity and character of traffic upon the public road; and what is generally, under comparable circumstances, considered to be reasonable, provided that in no event shall the railroad be required to pay more than 50 percent of the cost of a grade crossing elimination project on a county road system or on a municipal street system. In the event agreement cannot be reached, the determination of what portion of the costs shall be the fair and reasonable share of the railroads involved shall be made by the department after reasonable opportunity for hearing to all parties concerned. In making such determination, the department shall give due regard to the considerations heretofore enumerated. The agreed value or, in the absence of agreement, the independently appraised value of the fee or any lesser interest in the right of way of the railroad used for such project shall be determined and such value credited to the railroad as a part of its participation in the cost of the project, provided that nothing in this Code section shall prevent the department, county, or municipality from exercising its rights of eminent domain as now or hereafter provided by law.

(2) As used in this subsection, the term "costs of the project" means:

(A) In the case of a project for part of a county road or municipal street system, the total costs of such project less the sum of any funds for such project furnished by the federal and state governments; and

(B) In the case of a project for part of the state highway system, the total costs of such project less any funds furnished by the federal government.