That junction was not the same in 1950s when he had his accident there, I remember a large tree being in the pictures taken there back then. I think his car hit the tree also or maybe that was all they hit
I've driven around that area a bunch back in the mid 1990s doing my work for the phone company, I think remember that sign being there then, maybe not
I think they had driven from Hollywood up to Oxnard and then up towards Taft, all the roads back then were two lanes, no freeways like today