B752 LOSE TXWY ORIENTATION AND TAXI ONTO CLOSED PORTION OF TXWY AT LAX.

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ON TAXI TO RWY 25R; THERE WAS A SEA OF YELLOW FLASHING LIGHTS AROUND APCH END OF RWY 25L AND TXWY B. TWR CLRED US TO TURN R ON TXWY F; CROSS RWY 25R AND HOLD SHORT OF RWY 25L. I TURNED TO MAKE THE PA 'FLT ATTENDANTS PLEASE BE SEATED FOR DEP.' I RECEIVED A CREW CALL FROM THE FLT ATTENDANT. SHE SAID THEY WERE NOT QUITE READY. I LOOKED UP AND SAW WE WERE SLIGHTLY PAST TXWY F; AND SAW THAT WE WERE ABOUT TO TAXI OVER 2 TEMPORARY RED LIGHTS SET TO INDICATE THE CLOSED PORTION OF TXWY B. I IMMEDIATELY TOLD THE CAPT 'STOP; BARRICADE; STOP!' HE BROUGHT THE ACFT TO A COMPLETE STOP. HE ASKED IF THERE WAS ROOM ON MY SIDE TO TURN AROUND. THERE WASN'T ROOM. HE STARTED TO TURN L; BUT STOPPED WHEN IT WAS CLR THERE WAS NOT ENOUGH ROOM ON THAT SIDE. I CONTACTED TWR; EXPLAINED THE SIT. THEY SENT 2 CARS FROM THE 'CITY' TO REOPEN TXWY B. WE PROCEEDED TO THE CARGO RAMP AREA; PERFORMED A L 180 DEG TURN BACK TO TXWY F; AND PROCEEDED TO HOLD SHORT OF RWY 25L. DEP WAS COMPLETED WITHOUT FURTHER INCIDENT. THE YELLOW FLASHING LIGHTS WERE SO BRIGHT THAT THEY CREATED CONFUSION AS TO WHAT PART OF TXWY B HAD BEEN CLOSED. THE TEMPORARY RED LIGHTS; INDICATING THE CLOSED PORTION OF TXWY B; WERE DIMLY LIT AND THERE WERE ONLY 2 OF THEM. THE LIGHTING SIT WAS VERY CONFUSING.