The Missouri Department of Transportation (MoDOT) in cooperation with the St. Louis County Department of Highways and Traffic (DHT) expanded Route 141. 1 between just south of Ladue Road (Route AB) to Olive Road (Route 340). DHT extended Route 141 from Olive Road to the Page Avenue Extension (Route 364) at the Maryland Heights Expressway which links to the Earth City Expressway which continues north to Route 370 where it then turns into Missouri Bottom Road via Aubuchon Road. SPUIs were constructed at Ladue Road and Olive Blvd.