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Alto Tunnel Study Now Under Way

Posted: 2013-08-04

Additional detailed study of the Alto Tunnel and its approaches is now under way.  This additional study is in two phases, the first conducting a land survey and researching real estate, easement, and ownership issues and the second will be a geotechnical analysis of the tunnel structure.  The Board of Supervisors approved the contract for the first phase of the contract.

The additional study is an outcome of the 2010 Mill Valley-Corte Madera Corridor study which looked at three routes for bicyclists and pedestrians to get between the two communities:  Camino Alto/Corte Madera Avenue and Horse Hill, both existing routes, and the Alto Tunnel route.  The 2010 study revealed that the significant number of unknowns with the tunnel route made it difficult to evaluate the feasibility of reopening the tunnel without additional information. 

The area of the study extends from the north end of the Mill-Valley Sausalito path at Vasco Court in Mill Valley to the south end of the Corte Madera-Larkspur path at Tamalpais/Redwood Drive in Corte Madera.  Get more information on the study by visting the study's website at:

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