The tunnel would run from the top of Shamrock Ranch in Pacifica (see map) to about 1000 ft north of Green Valley and the Northern Park Boundary where it would rejoin the existing highway.


About 160 - 200,000 cubic yards of earth would need to be excavated for the tunnel. The material would be used to construct the approaches at each end, so no material would need to trucked in or hauled away.

Environmental Process:

A revision of the Federal Environmental Impact Study (FEIS) would be necessary to designate the tunnel as the preferred alternative, taking about 6-12 months.