The old I-80 was not signed as SR 51, but as a business route. Unlike most business routes in California, which run along locally-maintained streets through a downtown area, Business 80 was not assigned to the pre-freeway alignment of US 40, but to a freeway. The existence of two freeways, both numbered 80, caused some confusion, and in 1996 the full route was given the Capital City Freeway name at the request of the Sacramento Area Council of Governments. This name appears on overhead signs at prominent interchanges. The route is referred to as Business 80, Biz 80, Capital City Freeway, Cap City Freeway, and US 50 (western section only) by residents and mapmakers. Caltrans does not normally use the Business 80 designation, except for signage and other related concepts like Cal-NExUS exit numbers (which are continuous along the business loop). Caltrans refers to the western half as US 50 and the eastern half as SR 51 for traffic condition reporting.