California State Route 37 (SR 37) is a 21-mile long state highway that connects Interstate 80 in the Solano County city of Vallejo with U.S. Highway 101 in the Marin County city of Novato. Running along the northern shore of San Pablo Bay, SR 37 is the most direct connection between eastern and western portions of the North Bay, and therefore serves as a vital link for travelers traveling between Solano, Napa, Sonoma, and Marin Counties.

Although the corridor has been proposed to be upgraded to freeway standards since the 1950s, due to various environmental and economic challenges it exists as a two-lane highway for most of its length and consistently suffers from heavy congestion and travel time delays. Resulting from these issues is an interest among North Bay jurisdictions, including the transportation authorities of Solano, Napa, Marin, and Sonoma Counties, to explore the feasibility of an optimized transit solution for the SR 37 corridor that would better enable travelers to connect across the North Bay without a private vehicle and also alleviate the continuing traffic congestion along SR 37 (estimated in 2019 at 13-hours a day). With this plan, the Solano Transportation Authority (STA) is building upon the findings of a previously completed SR 37 Travel Behavior and Transit Feasibility Study (2019) to identify appropriate mobility solutions for the corridor that are both feasible and data informed.

PDF California State Route 37 Express Bus/TDM Plan March 2024