While preparing the May 2002 Draft Environmental Impact Statement/Environmental Impact Report for the Willits Bypass Project, Caltrans studied over 30 potential routes and narrowed them down to four viable alternatives. More details about these routes can be found in the document Alternatives Considered But Eliminated From Further Study (PDF 58K).
The four routes remaining were studied in even greater detail. After holding public meetings and soliciting public input, Caltrans received and reviewed hundreds of public comments (See Section 2 of the October 2006 Final Environmental Impact Statement / Environmental Impact Report), and working very closely with the U. S. Environmental Protection Agency and the U. S. Army Corps of Engineers, it was determined that a modified version of Alternative J1T would be the Least Environmentally Damaging Practicable Alternative. The result is the route we have begun to construct.