The goal of the 2009 Sepulveda Pass Freeway Expansion Project seemed simple. A carpool lane was to be added to reduce congestion on a 10-mile stretch of Los Angeles’s I-405 freeway, the second most congested road in the U.S. However, this brought exceptional technical and logistical challenges—the project required carving through a mountain, demolishing and replacing three overpasses, and moving a 60-year-old street, all alongside a freeway that saw 500,000 commuters daily.
