The artery that connects Hazel Green and Meridianville to downtown Huntsville is doing more work every year, with the same lane count, the same intersections, and the same priority queue at ALDOT.
US 231 is not a state highway problem solved by adding lanes. It's a population-growth problem that has outpaced the planning cycle that funds it. Madison County is one of the fastest-growing counties in the state. The transportation infrastructure that serves it operates on a state-level allocation rhythm that updates years after the demand has shifted.
That gap is where the cost lands.
Whether by passing legislation or organizing community pressure on ALDOT, progress will be made.