U.S. Route 40 Alternate was an alternate route of US 40. In 1960, a portion of US 40, as well as US 66, was moved onto the new freeway (signed as part of I-55/I-70). As a result, the former routing was signed as US 40 Alt. In 1963, US 40 and US 66 were realigned onto a newer portion of the freeway from IL 157 to Exchange Avenue. Then, as a result, the alternate route extended southwest to Exchange Avenue. In 1964, a freeway connection between Exchange Avenue and Veterans Memorial Bridge was made. As a result, US 40 Bus. was extended due southwest to East St. Louis, supplanting part of the alternate route.
