Route 78 is from:
(a) Route 5 near Oceanside to Route 15 near Escondido.
(b) Route 15 near Escondido to Route 86 passing near Ramona, Santa Ysabel, and Julian.
(c) Route 86 near Brawley to Route 10 near Blythe.
The portion of the route described in subdivision (c) between the easterly junction of Route 115 and the Imperial-Riverside county line shall be known and designated as the “Ben Hulse Highway.”