The mechanism. The IIJA expires September 30, 2026, and the House Transportation and Infrastructure Committee has already cleared its replacement: the BUILD America 250 Act (H.R. 8870), a five-year, $580 billion package that passed committee 62-2. The bill guarantees $474.4 billion in formula-driven Highway Trust Fund contract authority — the money that flows to state DOTs by statutory apportionment, largely tracking lane-miles, population, and existing federal-aid highway mileage — while also standing up new competitive pots: a $12 billion Surface Transportation Accelerator Grant program and a $10 billion Competitive Highway Bridge program, both discretionary and awarded project-by-project out of Washington. That split matters more than the topline number. Formula dollars reliably follow states with the most existing Interstate and federal-aid mileage; discretionary dollars follow whichever states write the best applications for new capacity — disproportionately fast-growing Sunbelt metros racing to keep up with population growth. Aggregates producers don't care about the bill's size so much as which spigot it favors, because that determines whose quarries get the truck traffic.
Who cashes in. Martin Marietta (MLM) is the formula play: its footprint is weighted toward the Carolinas, Texas, Florida, and the Southeast's existing federal-aid highway corridors, and the Lhoist North America combination just deepened that Southeast/Southwest density — a formula-heavy bill rewards incumbent lane-miles, which is MLM's core turf. Vulcan Materials (VMC) is the discretionary and rooftop play: with roughly 425 active aggregates facilities concentrated in Sunbelt metros still building new capacity (Dallas-Fort Worth expansion, Colorado entry), VMC is better positioned when new competitive grants fund greenfield interchanges, bypasses, and metro-area widening tied to residential growth rather than just resurfacing what already exists. Caterpillar (CAT) cashes in either way — more federal-aid dollars, formula or discretionary, means more earthmoving equipment utilization at quarries and job sites nationwide. Nucor (NUE) benefits from any bridge-heavy allocation, since the new $10 billion Competitive Highway Bridge Program is rebar- and structural-steel-intensive in a way flat resurfacing work isn't.