Every operator of a vehicle traversing the intersections designated as stop intersections in § 421-1, 421-2, 421-3, 421-4, 421-5, 421-6 and 421-7, above, shall stop such vehicle before entering said intersection; provided, however, that said intersection is clearly marked by a sign placed in accordance with the laws of the State of California and as provided in this chapter. (Ord. 950, § 2, 10/17/1973; Ord. 1621, § 1, 12/6/1983)