Plans to upgrade SR 1 to a freeway from its southern terminus all the way to Oxnard, including building an offshore causeway from the Santa Monica Pier to Topanga Canyon Boulevard south of Malibu, were ultimately killed by 1971 due to local opposition. In 1980, another section was added northwest of Ventura near Emma Wood State Beach, when several miles of the old two-lane alignment of U.S. Route 101 were posted as SR 1 where the freeway had bypassed it in about 1960. Then in 1988, the segment from Purisima Road in Lompoc to SR 135 was re-routed from Harris Grade Road to the former County Route S20 so it could directly serve Vandenberg Air Force Base.