Are you allowed to overtake the emergency vehicle beyond this sign?

Why?

The D-43 sign marks the end of the built-up area. The prohibition on overtaking an emergency vehicle operating with priority applies within built-up areas. Beyond this sign, you may overtake it if the manoeuvre is safe, complies with all other rules and does not obstruct its progress.

art. 24 ust. 11 oraz art. 9 ust. 1 Prawa o ruchu drogowym