Inside Seven
Current Issue: September 2014
The first highway to across a major mountain range, the original Ridge Route was officially designated a Historic Civil Engineering Landmark near Pyramid Lake, adjacent to Interstate 5.

by  Jeanne Bonfilio
Issue Date: 11/2008

A historical monument designation is placed to mark milestone achievements of transportation pioneers

In 1915, along the rolling hills above Interstate 5, in north Los Angeles County, a roadway still known as the original “Ridge Route” was carved out of a mountain by forward-thinking transportation pioneers. It was a two-lane, gravel, partially paved narrow and winding roadway – that lined the way for the modern roadways of today – especially and particularly the Golden State Freeway or I-5.

Last month, on October 18, through the efforts of the American Society of Civil Engineers (ASCE), the Ridge Route Preservation Organization and transportation historians, the “Ridge Route” was officially designated a Historic Civil Engineering Landmark.

Dan Freeman, Deputy District Director for Maintenance, represented Caltrans at the Pyramid Lake Recreation Center to officially place the historical monument designation on the famous Ridge Route along I-5 to memorialize and celebrate the historic achievements of transportation pioneers.

The Ridge Route was initially a 53-mile portion of the first 123-mile roadway that was constructed between Los Angeles and Bakersfield, primarily by pick and shovel. The route has rich history and beauty all its own, complete with scenic views of Castaic Lake, the rolling hills of the Tehachapi Mountains and the San Joaquin Valley. It was constructed through the Tehachapis over the Tejon Pass and down the “Grapevine” grade. It was named that way because the major portion of the road was placed on the ridge of the mountains west of Castaic Creek to avoid drainage problems and reduce maintenance and earthwork. It was the very first highway to cross a major mountain range and began a physical connection, a critical link between northern and southern California.  And it was "the first highway crossing of a major mountain range by the newly formed California State Department of Highways," according to the writing on the new monument.

When the Ridge Route was built, Pyramid Lake was just a river and there was no freeway. In those very early years of highway building, the area was studied by Caltrans engineers and surveyors, who made their way on foot along the Ridge Route and what is now the eight-lane I-5. According to one of Caltrans early surveyor, Dick Murphy, who recently retired, “This was a daunting challenge for California’s highway engineers working for the Division of Highways back then.” He and a team of engineers and surveyors walked that distance from Castaic to the Kern County line, over 30 miles one way, to map out the alignment of I-5, eventually transformed a huge mountain into a landmark in freeway surveying, planning, engineering, construction, operations and maintenance – or the famous Golden State Freeway – the backbone of the state highway system.

“They are some of the transportation heroes of the era of highway building,” Freeman added. On behalf of Caltrans, Freeman publicly thanked Don Sepulveda, Warren Minner and ASCE members; Harrison Scott, President of the Ridge Route Preservation Organization; Andy Machen, P.E., Caltrans District 8; and the United States Forest Service for their efforts to preserve the rich history of this famous roadway.


On August 18, 1915, pioneer highway engineers are rolling and tamping (leveling) concrete pavement on the original Ridge Route.  Also on August 7, 1915, workers are placing reinforcing steel rods in concrete pavement. At the podium is Dan Freeman, Deputy District Director for Maintenance accompanied by, left to right, historian  Harrison Scott, Warren Minner and Don Sepulveda. With the famous Interstate 5 in the background, Dan Freeman gets ready for a closer look at the new historical monument.