Traffic came to a halt on Sunset Boulevard this afternoon after a head-on crash prompted authorities to close all lanes. Shortly after 4 p.m., a UCLA police unit responded to a crash on the busy artery between Veteran and Bellagio, finding multiple victims trapped. "All lanes of Sunset Boulevard closed by head-on crash. Avoid this afternoon if possible," warned UCLA's Newsroom on Twitter. The road is closed for about 3/4ths of a mile between Veteran and Westwood Plaza. The LAFD responded to the scene and transported at least one person to a local hospital.