Portal:California roads/Selected article/6

State Route 37 (SR 37) is a state highway in the northern part of California that runs 21 miles (34 km) along the northern shore of San Pablo Bay. It is built from U.S. Route 101 in Novato and runs through the southern tips of Sonoma and Napa counties to Interstate 80 in Vallejo. It serves as a vital connection between the four counties of the North Bay Area, north of San Francisco. SR 37 has been proposed to be built to freeway standards since the early 1950s. However, the proposal was met with many economic and environmental obstacles, making the task all but impossible for much of the route. Notable problems included a levee break in Vallejo which turned part of the land around the highway into a marsh that is home to endangered species, and a section of highway known as "Blood Alley" for its high rate of fatal accidents.