(1) For the purposes of this section, the following terms shall have the meanings ascribed to them in this subsection:
(a) “Deficient bridge” means a bridge that is eligible for replacement or rehabilitation as determined by the National Bridge Inspection Standards sufficiency rating and that is included on the latest annual official bridge inventory prepared by the Office of State Aid Road Construction as a bridge having a sufficiency rating of fifty (50) or less, excluding bridges on the state aid road system, the municipal urban system and the rural major collector system.
(b) “Local system road miles” means all highways, roads and streets within a county, including highways, roads and streets within incorporated municipalities of the county, that are not included on the designated state highway system.
(2) From the funds on deposit and credited to the Local System Bridge Replacement and Rehabilitation Fund created in Section 65-37-13, each county shall be allocated a percentage of such funds as they become available, which percentage shall be based:
(a) One-half (½) on the proportion that the total number of deficient bridges in the county bears to the total number of deficient bridges in all counties of the state; and
(b) One-half (½) on the proportion that the total number of local system road miles in the county bears to the total number of local system road miles in all counties of the state.