Question: Sacramento Mather Airport is located on the site of a former air force base, located 12 mi east of Sacramento, on the south side of U.S. Route 50 in Sacramento County, California, which was closed in what year?
Sentence (from "Tower Bridge (California)"): It was previously a part of U.S. Route 40 until that highway was truncated to east of Salt Lake City.
Relevant evidence: No