on August 24, 1970, at a cost of $103 million (about $ in ). Portions of the old road continued to exist as a county road. The longest preserved segment was the part bypassed by the Ridge Route Alternate, between Castaic and SR 138 near Sandberg, including the portion through the Angeles National Forest. The road for about south from SR 138 is part of CR N2. Harrison Scott, a retired engineer, was traveling north on I-5 with his son in 1991, when his son speculated about the difficulty of driving over the first road through the rugged terrain. Having some extra time, and recalling a drive on the old road in 1955, they left the freeway and traveled along most of the abandoned section. Near SR 138, Scott asked a county road crew which was resurfacing the road if it was still maintained by the county, and the crew replied that they didn't know who maintained it through the desert. It turned out that the county officially owned it but did not maintain it; Scott has since convinced the county and forest to exchange ownership with the Santa Anita Canyon Road, then a county road. For the next six years Scott worked to get the road added to the National Register of Historic Places, and finally succeeded when, on September 25, 1997, the National Park Service added the in the forest to the National Register. He later used his research for the National Register application to write a book, Ridge Route: The Road That United California, published in 2002. The Ridge Route was also designated as a California Historic Civil Engineering Landmark by the American Society of Civil Engineers in 2008. The route was repaired in 2005 following heavy rainfall, but the road was not reopened , due to objections from Angeles National Forest officials. Major intersections See also 1857 Fort Tejon earthquake Mountain Communities of the Tejon Pass References Further reading External links Ridge Route Preservation Organization Harrison Scott's Ridge Route Site (includes information on the roadway as well as a book for sale) Historic Highway 99 Association of California Historic US 99 Guide: The Ridge Route (includes detailed history of the Ridge Route Alternate and Interstate 5) Virtual Tour of the Ridge Route (includes detailed history of the Ridge Route Alternate and Interstate 5) (mostly old postcards) Named highways in California Roads in Los Angeles County, California