Mysterious Santa Anita question

[jnunan4759]

If you watch a 6 1/2 F Turf (Hill) race at SA. You see a thin red and white striped pole just off the track to the right of the gate. It has a fairly large yellow hoop on top. It's at least 15 feet tall. I've asked a lot of people there and never got an answer beyond speculation. It must serve a purpose because it always looks painted and maintained.

Any answers ?