California State Route 237

State Route 237 runs from El Camino Real in Mountain View to Interstate 680 in Milpitas. It runs south of the San Francisco Bay, connecting the East Bay to the Peninsula.Route descriptionRoute 237 begins at a junction of Grant Road with El Camino Real in Mountain View, as a freeway with two lanes in each direction, although most traffic comes from California State Route 85. Westbound traffic can connect to Route 85 southbound, but the eastbound traffic connection to Route 85 northbound is labeled as an exit for U.S. 101. Route 237 intersects with Highway 101 at the southern corner of Moffett Field. After this intersection, a carpool lane is added, for a total of three lanes in either direction. It remains like this until the east end of the freeway at Interstate 880, where most eastbound traffic is directed to northbound I-880. The route then becomes a city street, Calaveras Boulevard, in Milpitas, terminating at Interstate 680.Exit signs from U.S. 101 north to Route 237 west currently say "Mountain View-Alviso Road". Starting from half a mile after the highway's western terminus, and ending at the I-880 intersection, Route 237 is mostly constructed to Interstate standards, and is named the Southbay Freeway. It is not part of the Interstate system, however.