State Route 75 (SR 75) is a expressway in San Diego County, California. The state highway is a loop route of Interstate 5 (I-5) that begins near Imperial Beach, heading west on Palm Avenue. The route continues north along the Silver Strand, a thin strip of land, through Silver Strand State Beach. SR 75 passes through the city of Coronado as Orange Avenue and continues onto the San Diego–Coronado Bay Bridge, which traverses the San Diego Bay, before joining back with I-5 near downtown San Diego at a freeway interchange. The Silver Strand Highway was constructed and open to the public by 1924. What would become SR 75 was added to the state highway system in 1933, and designated Legislative Route 199 in 1935. SR 75 was not officially designated until the 1964 state highway renumbering. The Coronado Bay Bridge opened in 1969, and provided a direct connection between San Diego and Coronado. Since then, various proposals have taken place to relieve commuter traffic between San Diego and Naval Air Station North Island that traverses the city of Coronado. However, none of these proposals have gained support, including an attempt in 2010. Route description SR 75 begins as Palm Avenue at I-5 in the Nestor neighborhood of San Diego, heading westbound from the Southland Plaza shopping center. The route travels between the communities of Palm City and Nestor before entering the city limits of Imperial Beach. There, SR 75 curves to the north, becoming Silver Strand Boulevard and crossing into Coronado. SR 75 continues onto the peninsula containing Coronado Island, separated from the mainland by San Diego Bay. The highway passes through the Silver Strand Training Complex and the South Bay Study Area before entering the Coronado Cays subdivision and paralleling Silver Strand State Beach. After this, SR 75 passes through the United States Naval Amphibious Base for a few miles before entering downtown Coronado. The highway becomes Orange Avenue and turns north-northeast as the main street through Coronado. SR 75 intersects SR 282 at the one-way couplet of Third and Fourth Streets; SR 282 continues west on Third Street and returns to SR 75 on Fourth Street, while SR 75 continues east on Fourth Street and heads west towards Orange Avenue on Third Street. The one-way couplet is brief, and SR 75 becomes a divided highway before crossing the Coronado Bridge. While on the bridge, SR 75 crosses into