Good Afternoon, a colleague and I are debating whether the following sentence exhibits a passive construction or a copular/linking verb and a predicate adjective:

The roads and ports are closed due to the weather conditions.

Observations are (1) the structure is passive, merely missing/excluding the prepositional phrase that would house the actor, e.g. "The roads and ports are closed by the magistrate due to the weather conditions"; (2) the sentence is simply one which exhibits a copular/linking verb, "is," and a predicate adjective, "closed."

But I also have a spin-off question: can both structures exist simultaneously? Is the nature of passive voice to exhibit a copular/linking verb with a predicate adjective?

Thank you.

Best,
Larry