Are you allowed in this situation to change the lane you are taking when you intend to go straight?

Why?

Your lane is for turning right, while the adjacent left lane continues straight ahead. The broken line between them allows you to change lanes. Take particular care, signal your intention and give way to vehicles already in the left lane.

§ 86 ust. 1 i § 87 ust. 1 rozporządzenia w sprawie znaków i sygnałów drogowych; art. 22 ust. 1, 4 i 5 Prawa o ruchu drogowym