(1) "Betterment" means any construction or reconstruction on a state aid-designated road which results in an improvement which exceeds or equals any previous improvement whether or not the previous improvement was financed in part or in whole through the provisions of this subchapter;

(2) "Construction", "reconstruction", or "improvement" means any proposal submitted by a county court which meets the definition of betterment as opposed to maintenance;

(3) "Maintenance" means any act of work which maintains the improvement in serviceable condition;

(4) "State aid", by way of funds to be expended on state aid roads, means any sum or sums provided by the General Assembly to supplement funds furnished by the several counties for the purpose of constructing, improving, widening, straightening, surfacing, or reconstructing roads on the state aid system and shall be available to the several counties in a proportion to be fixed and determined by law; and

(5) "State aid roads" means that classification of county roads, including bridges and ferries, composing the major collector and minor collector routes feeding into local trade areas or into the state highway system, which are not designated as state highways, and particularly those essential to the conservation and development of natural resources, of economic and social value and encouraging desirable land utilization, having in addition one (1) or more of the following characteristics:

(A) They extend to the larger communities, including all incorporated towns;

(B) They connect with roads of major importance in adjoining counties;

(C) They connect with the state highways to form a complete network of main feeder roads;

(D) They carry heavy volumes of traffic serving major business and agricultural interests of the county; and

(E) They collect traffic at reasonable intervals from several local roads.