The person who took this photo was rather bravely standing in the middle of the Hollywood and Vine intersection at night, pointing his camera southward. We can see the hat-shaped neon Brown Derby sign on the left, and farther down on the right the angled sign for Tom Breneman’s. Wrapping around the Taft building (left) is the KFWB flashcast which started on August 6, 1946, so this photo is circa late 1940s. But look at that tiny “No Left Turn” between the streetcar tracks on Hollywood Blvd. How many times a year did they have to replace that?
you can see the “No left turn” from a different angle here. I’d guess it was rolled out there by the beat cop as needed. https://imgur.com/YvffVPk
That one looks bigger and more portable. But it would make sense that the could set them up as needed, doesn’t it?
I think the one in your pic is just turned to a different angle. You can see the top half in this pic.
https://i.imgur.com/XuMJQD8.png