Heads up, all you students moving back to UCLA this weekend. You might want to factor in a little extra time or a detour if your plan is to exit the 405 at Sunset Boulevard. Due to Sepulveda Pass Improvements Project construction, the northbound I-405 off-ramp at Sunset will be closed for the weekend and a lane reduced in each direction on the Sunset Boulevard Bridge. (One lane in each direction will remain open.) Closures will begin at 9 p.m. Friday, Sept. 16, with reopening set for 6 a.m. Monday, Sept. 19.