Until Interstate 5 cut through the Angeles National Forest, the Ridge Route was the only road connecting coastal Northern and Southern California. Opened in 1915, it wound from around Castaic north of Los Angeles to around Lebec, including the "Grapevine" just south of the later junction of Interstate 5 with State Route 99. The old highway climbed through a northern area in the San Gabriel and Tehachapi Mountains, including a place where the original wagon drivers had to cut their way through thick grapevines. The date is derived from Teich's number at the top of the dividing line on the back, A-84437.
