The Caldecott Tunnel Fourth Bore Project, which will alleviate traffic congestion on State Route 24 between Contra Costa and Alameda counties in northern California, is in track to open by the end of the year, according to the California Department of Transportation (Caltrans). The tunnel was constructed using Sequential Excavation Method / New Austrian Tunneling Method (SEM / NATM) techniques and is approximately 3,400 feet ( 1,000 meters) long. Follow the link to a news clip for more information on the opening of the Caldecott Tunnel 4th Bore. For more information on GZ’s involvement with the Caldecott project, visit the project page.