This was back in the 50's and I was just a kid. Long before I-5 was built. We were returning from a trip to my Uncle's place which was southwest of Gridley California so somewhere south of Yuba City. Saw the signs a couple of times on different trips to visit relatives. Can't help you with why they didn't rhyme but to me the signs were the highlight of the trip. As seen from the backseat of a 49 Pontiac.