San Luis Obispo, CA -- Highway 166 reopened at about 1:15 yesterday afternoon after a semi truck rolled over, shutting it down for hours. The CHP says at about 9:30, 50-year-old Anthony Whitehead of Atlanta was driving the truck eastbound on Highway 166, just east of Alamo Creek Road, when he drifted off the roadway onto the shoulder. Whitehead tried to get back onto the roadway, but lost control of the truck and it overturned. Both lanes were blocked. Whitehead was not hurt. Traffic was diverted to Tepusquet Road.