Caldecott Tunnel fourth bore nears end of big dig

A roadheader inside the Caldecott Fourth Bore Tunnel

A roadheader inside the Caldecott Fourth Bore Tunnel

The 2-year process of excavating the 3,389 foot long fourth bore of CALTRANS’ Caldecott Tunnel is nearly complete. The tunnel is anticipated to be put into service in 2013 to help relieve a major traffic bottleneck in the San Francisco Bay area. [Source: ContraCostaTimes.com via ASCE SmartBrief. Image: Karl Mondon / San Jose Mercury]