I agree, avoid UN avenue at all cost. May hinukay sila from the corner from M. Orosa to Taft avenue. Sobrang traffic, lalo na kung umulan. I know because I work in the area.
Another road to avoid when there is high tide is TM Kalaw, from Taft avenue to M. Orosa too. It gets flooded there with foul smelling waters during high tide. I think they have damaged the drainage system there when they repaired the sidewalks a few months back. We have reported it to DPWH but nothing yet. Sabi ng mga guwardiya, high tide daw kasi. But how come from Taft ave to M. Orosa lang ang flooded, both sides pa? Pero as you near Luneta, wala namang tubig. Palagay ko, may bara mga drainage canals, hindi maka flow out to the sea.