These white street signage poles are not secure. Don't lock your bike to them if you can help it.
They are easily removable from the ground and are a popular target by bike thieves.
Don't expect any security from wrapping a lock around this pole - it's only marginally useful as something to lean your bike against.
If you must leave your bike leaned against a removable street sign pole, please make certain you lock your wheel somehow. This stops your bike from being immediately rideable without further work by the thief.
For more information to help you keep your bike safe from being stolen including choosing a good lock, and registering your bike with 529 Garage, check out the following pages: