Interstate 44 (I-44) is a major Interstate Highway in the central United States. Although it is nominally an east–west road as it is even-numbered, it follows a more southwest–northeast alignment. Its western terminus is in Wichita Falls, Texas, at a concurrency with U.S. Route 277 (US 277), US 281, and US 287; its eastern terminus is at I-70 in St. Louis, Missouri. I-44 is one of five Interstates built to bypass US 66; this highway covers the section between Oklahoma City and St. Louis. Virtually the entire length of I-44 east of Springfield, Missouri, was once US 66, which was upgraded from two to four lanes from 1949 to 1955. The section of I-44 west of Springfield was built farther south than US 66 in order to connect Missouri's section with the already completed Will Rogers Turnpike,