The first direct auto connection between Southern and Northern California and probably saved California from becoming 2 states. It was known for it's hairpin turns and it has been said that if they were all joined they would make 119 full circles. In 1997 it was places in the National Register of Historic Places. It didn't last very long from its completion in 1915, as in 1933 the Ridge Route Alternate, former US Highway 99 was constructed bypassing the hazardous road, although the orignal portion in the Pyramid Lake area of the alternate is now under the reservoir. The Ridge Route began at Castaic Junction (Where Interstate 5 meets California 134) and ended at bottom of the Grapevine Grade.