The General Douglas MacArthur Causeway is a six-lane causeway that connectsDowntown Miami to South Beach via Biscayne Bay in Miami-Dade County. The highway is the singular roadway connecting the mainland and beaches to Watson Island and the bay neighborhoods of Palm Island, Hibiscus Island, and Star Island. The MacArthur Causeway carries State Road 836 and State Road A1A over the Biscayne Bay via a girder bridge. Interstate 395 ends at Fountain Street, the entrance to Palm Island Park which has a traffic light as well as bus stops.