Today, if you wish to drive north from Los Angeles towards the San Joaquin Valley, you can comfortably speed along the eight-lane Interstate 5. This was not always so. From 1915 to 1933, motorists navigated 48 miles of torturous hairpin curves and steep grades along the Old Ridge Route between Castaic and the Grapevine. The exhausting trip (speed limit: 15 mph for cars, 12 mph for trucks) easily took an entire day. The route was replaced in 1933 by the much straighter, wider and less harrowing Highway 99, also known as the Alternate Ridge Route. Interstate 5 opened to motorists in 1960.
Of interesting note: The Old Ridge Route was one of the first projects of the newly formed California Highway Commission and was considered a superhighway for its day. Historians note that this road link between Southern and Central California may actually have saved California from splitting into two states.