and Genesee Avenue, SR 52 intersects I-805 before exiting the canyon and traveling along the southern edge of the MCAS Miramar military base. From I-805 to SR 163, the highway goes through an area with visible Pliocene sedimentary rocks estimated to be 10 million years old. After passing the Miramar Recycling Center and an interchange with Convoy Street, SR 52 intersects SR 163, a freeway heading towards downtown San Diego. SR 52 intersects Kearny Villa Road before an interchange with I-15. A collector-distributor road serves these three interchanges. After this interchange, the freeway leaves the edge of the military base and enters the San Diego neighborhood of Tierrasanta, where there is a junction with Santo Road, before traversing Mission Trails Regional Park, an open space preserve, for a few miles. The freeway ascends to Mission Trails Pass, north of the summit of Fortuna Mountain. The mountain is part of the Peninsular Range; the highway cuts through Eocene rocks estimated to be 50 million years old and marine fossils. The road on the eastern side of the mountain is carved out of "igneous granitic rocks" that are thought to be 150 million years old, an unusual formation compared to the Eocene layer. A dedicated two-way bicycle path exists on the northern side of the roadway between Santo Road and Mast Boulevard, with access possible from both termini. East of the Mast Boulevard interchange, SR 52 crosses and begins to parallel the San Diego River. The freeway enters the city of Santee, where SR 52 was built alongside Mission Gorge Road. SR 52 intersects the northern end of SR 125, where SR 52 traffic can exit south onto SR 125. The freeway continues east through Santee, with interchanges at Fanita Drive, Cuyamaca Street, and Magnolia Avenue, before it comes to an end at SR 67. SR 52 is part of the California Freeway and Expressway System and is eligible for the State Scenic Highway System. In 2016, Caltrans officially designated the segment adjacent to Mission Trails Regional Park between Santo Road and Mast Boulevard as a scenic highway. SR 52 is also part of the National Highway System, a network of highways that are considered essential to the country's economy, defense, and mobility by the Federal Highway Administration. The entire route is known as both the Soledad Freeway and the San Clemente Canyon Freeway. In 2013, SR 52 had an annual average