As a major east-west connector through southern Calaveras County, SR 4 provides access from the San Joaquin Valley to the Sierra Nevada Mountains. Within the County, the two-lane highway traverses mostly rural farmland, characterized by a rolling terrain that supports rock outcroppings, seasonal streams, and natural vegetation, as well as agricultural operations. This first phase realigns approximately three miles of SR 4 from Bonanza Mine Way to Appaloosa Road to meet current design standards, as well as enhance safety and improved sight distance. The project includes multiple box culverts from 50-100 feet in length, 60” diameter reinforced concrete pipe drainage structures, numerous cast-in-place concrete retaining walls, and 3,000-feet of MSE walls. UNICO is providing construction management, inspection, office engineering, and labor compliance services.