What can one put on a street crossing or utility pole?

Googling online I see regulation on the municipal codes saying you can place advertisements on a utility pole, or street crossing pole. But it seems specific. Could you place a bird house? Or a little free library? Or even an umbrella?

Walking around town I often use the little lines of shade created from a traffic light or a street sign for shade when there’s no trees. Seems like in a hot city like Houston you’d expect much better shade infrastructure.

This is all I found:

http://houston-tx.elaws.us/code/coor_ch28_arti_sec28-39#:~:text=It%20shall%20be%20unlawful%20for,public%20place%20in%20this%20city.