In 1980, Madison County Transit (MCT) was formed, and assumed operation of bus routes in Madison County.
The following were the basic Bi-State Transit routes in Illinois.
501 - Caseyville-Collinsville - evolved from interurban railway route. Inherited from Caseyville Bus Line.
502 - Cahokia-Centreville - was always a bus route, forming a loop through those towns originating in St. Louis. Inherited from Industrial Bus Lines.
503 - Collinsville-Edwardsville - evolved from interurban railway route between St. Louis and Collinsville and Edwardsville. Inherited from Vandalia Bus Lines. Much of service assumed in 1980 by MCT, south portion became route 555.
504 - O'Fallon - evolved from interurban railway route. Inherited from Industrial Bus Lines and O'Fallon-Belleville Coach Co.
505 - Waterloo - evolved from East St. Louis Columbia & Waterloo Railway Co. interurban route, later St. Louis Red Bud & Chester Bus Co., later Gulf Transport Co. Later renumbered 502X.
510's - Alton local routes. Inherited from Citizens Coach Co. and affiliate Brown Motor Lines. Service assumed in 1980 by MCT.
530's - Granite City local routes. Inherited from Community Coach Co. Service assumed in 1980 by MCT.
560 - Belleville-St. Louis - evolved from interurban railway route. Inherited from Belleville-St. Louis Coach Co.
560's - Belleville local routes. Inherited from Belleville-St. Louis Coach Co. Part of route 564 to Scott Air Force Base and Mascoutah inherited from County Coach Co.
570's - East St. Louis local routes. Originally numbered in 700's. Inherited from East St. Louis City Lines.
In 2001, the new Metrolink light rail line was extended east from East St. Louis to Belleville. The bus routes were extensively restructured, with routes assigned new numbers starting with 1, and duplicating some route numbers in Missouri. And over the next few years, some routes were restructured further. The result is a significantly different route network, and no attempt is made to compare historic routes with the present routes.