Interstate 80 Business, called the Capital City Freeway in its entirety, is a business loop of Interstate 80 through Sacramento. Although signed as a business loop the route is actually two connected segments. The western segment is signed as U.S. Route 50 and carries the unsigned designation of Interstate 305. The unsigned designation of the eastern segment is State Route 51. The entire route is a freeway, and carried mainline Interstate 80 through Sacramento until the early 1980s. Portions of the eastern half were initially grandfathered into the Interstate Highway system; however, plans to upgrade or realign this portion to meet Interstate Highway standards were cancelled. As such, the I-80 designation through Sacramento was moved to a northern bypass of the city that had previously been signed Interstate 880, and the old route of I-80 through downtown was given the current business loop designation.