 The 3 @.@ 5 @-@ mile ( 5 @.@ 6 km ) portion of the SR 78 freeway in Oceanside opened to traffic on February 11 , 1954 . This highway was extended to Vista in May 1955 , at a cost of $ 1 @,@ 159 @,@ 000 ( about $ 25 @.@ 1 million in 2015 dollars ) . The part of the freeway from Vista to Escondido was one of the top priorities for highway construction in the county as early as 1960 . The center portion of the Vista Way Freeway opened in April 1962 , but the western part of the route was not entirely access controlled , as an expressway . The section of the SR 78 freeway from Rancho Santa Fe Road in San Marcos to Nordahl Road was completed in April 1962 . The part of the freeway connecting Rancho Santa Fe Road to the Vista portion opened in February 1963 , at a cost of $ 3 @.@ 9 million ( about $ 64 @.@ 5 million in 2015 dollars ) . The opening of the freeway was credited with helping to bring 315 jobs to San Marcos in 1963 . The rest of the freeway between Nordahl Road and US 395 opened on December 21 , 1964 , providing a four @-@ lane highway from Escondido to Oceanside ; the segment cost $ 1 @,@ 865 @,@ 000 ( about $ 30 @.@ 8 million in 2015 dollars ) . SR 78 was officially designated in the 1964 state highway renumbering . 
