Does the sign placed on the right roadway mean that it is closed to the traffic?

Why?

The white circle with a red border is sign B-1, which prohibits traffic in both directions. It is placed on the right-hand carriageway, so that carriageway is closed to vehicles and you must not enter it.

§ 16 ust. 1 rozporządzenia w sprawie znaków i sygnałów drogowych, B-1 „zakaz ruchu w obu kierunkach”