and Interstate 680 became more congested. Commuting from the San Joaquin Valley or the Tri-Valley to Silicon Valley required using a car or limited bus service.

In 1989, the San Joaquin Council of Governments, Stockton Chamber of Commerce, and the Building Industry Association of the Delta started work on a 20-year transportation plan for the northern section of the San Joaquin Valley. In November 1990, San Joaquin County voters passed