Since the mid-1940s, Kiewit Pacific Company has been building projects in California and Nevada. Some notable Northern California projects include the $90 million BART Rapid Transit Tube Tunnel between San Francisco and Oakland and the more than $1 billion San Francisco/Oakland Bay Bridge. The district is one of the most diverse units within Kiewit, performing construction of highways, bridges, dams, water treatment plants, telecommunications, grading and infrastructure and transit work. The district also operates precast concrete plants in California and Arizona. Kiewit Pacific Company is headquartered in Concord, Calif. .