Planning for I-805 began in 1956, and the route was officially designated in 1959 before it was renumbered in the 1964 state highway renumbering. Starting in 1967, the freeway was built in phases, with the northern part of the freeway finished before the southern part. I-805 was completed and open to traffic in 1975. Named the Jacob Dekema Freeway after the longtime head of the regional division of the California Department of Transportation (Caltrans), I-805 has been frequently cited for its complex engineering and architecture, including near I-8 on the Mission Valley Viaduct. Since then, several construction projects have taken place, including the construction of local and express lanes at the northern interchange with I-5. High-occupancy toll lanes are under construction on both the northern and southern portions of the route.