Are you allowed to make a U-turn at this junction?

Why?

You may make a U-turn at the junction shown, as junctions do not automatically prohibit this manoeuvre. Turn within the junction without crossing the double solid line on the approach. You must take particular care and avoid endangering or obstructing other traffic.

art. 22 ust. 1 i ust. 6 pkt 4 Prawa o ruchu drogowym