Historic US 99 Guide

The Ridge Route

[Pyramid Rock]

Pyramid Rock and Dam

As the picture shows, this rock got its name since its shape is an almost perfect pyramid. It was created when the flank of the hill was blasted away to make way for the road.

History of US 99 Over the Tehachipis

The next two sections of US 99 tour deal with the portion which goes through the mountains north of Los Angeles. This is one of the most interesting stretches of  old highways in California for a variety of reasons, ranging from geography to the amount of old road left intact. There are several roads that successively went through the Tehachapi Mountains which carried the US 99 shield and all offer excellent insight into the evolution of modern roads.

The Ridge Route

Prior to 1915 all traffic that wanted to go from Los Angeles to points north were compelled to either go by way of what is now current US 101 along the coast or by a circuitous route by way of Mojave and Bakersfield over what is now SR-14 and SR-58. The first highway built to cross the mountains directly was the Ridge Route, which was completed in 1915. When it was completed, not only did it save 50 miles versus the Mojave-Bakersfield route, it was also considered a miracle of modern engineering. While today it pales in comparison with current miracles, such as the Glenn Anderson (Century) Freeway, it shows a great deal of ingenuity in taking full advantage of limited resources. It had been built with minimal funds since the State of California had just entered the highway building business only a couple of years previously. Engineers needed to create a road with many sharp turns over a lengthy route so that a 6 percent slope could be maintained for its entire length. Remember that this was in the days when automobiles had little power, so creating a high speed straight alignment with steeper grades was not only moot, but somewhat senseless. Despite this, it represented a quantum leap in travel, making it possible to travel from Los Angeles to Bakersfield in less than a day.

Upon its completion in 1915, the Ridge Route was a graded dirt road with an oil surface, but it was soon paved with single slab concrete in 1919, a remarkable distinction for the time. The Ridge Route was paved for good reason since it soon became a very crowded highway, compelling a posted speed limit of 15 MPH. Even though it was considered and example of bold engineering achievement, between its construction in 1915 and its replacement by 1936, road engineering advanced quickly and by the mid 1920s, the winding concrete had already become obsolete. To help relieve congestion the road was straightened out by widening cuts to eliminate blind turns and adding asphalt, but even so it soon was apparent that a new road was needed.

The Ridge Route Alternate

Construction of a new alignment, the Ridge Route Alternate began in 1928. This new alignment was straighter and had gentler grades than the original Ridge Route. An article in California Highways and Public Works describes one of the many improvements over the old Ridge Route. "In traveling this highway the motorist need not fear that he will encounter a sharp curve at an unexpected place - there aren't any." Road building reflected the changes in automobile engineering. In 1915, a narrow road with sharp curves and a gentle gradient was more than sufficient for cars that could not go very fast. By the late 1920s, automobile technology had significantly advanced, with cars routinely able to exceed 60 MPH. This ushered in the era of high speed and well aligned roads, the products of faster vehicles.

The new road was built on a completely new alignment between Castaic School and Gorman since it was determined that further improving the existing highway was an impractical proposition. The alignment along the Piru Gorge had been considered for the original Ridge Route but was passed over in favor of the other alignment since private interests had planned to take advantage of their water rights by building a giant reservoir in the Piru Gorge, making prospect of paying for the right of way and the water rights too expensive to be justified at the time. (It is interesting to note the irony of the fact that the construction of Pyramid Lake forced the successor highway, I-5, to be built on a new and higher alignment 40 years later.)

By the end of the 1920s, traffic on the Ridge Route was very heavy and accidents were prevalent on this very dangerous road. While improvements had been made to improve the highway, more was needed. The fact that it had been given the US 99 designation in 1926 also gave extra impetus to upgrade the road since the mandate of the US Highway system was to use the shortest and safest routes. The new road was completed by 1933 and featured the latest improvements, which included a third suicide lane that enabled passing, albeit hazardously.

With the pavement from the realigned US 99 barely dry, the need to upgrade the route became apparent as traffic increased even more. Even though the Ridge Route Alternate was a major improvement over its predecessor, it was still unsafe in certain sections and it couldn't accommodate the explosion of traffic its completion created. Plans were made in 1940 to convert US 99 into four lane expressway, but  World War II delayed any further widening work until the end of the 1940s. The Collier Burns Act of 1947 provided funding for the widening work. Between 1948 and 1951 US 99 was transformed from a three lane mountain road into a modern four lane expressway. In 1954 a busy section of US 99 at the north end of the San Fernando Valley and the junction with US 6 was bypassed by freeway, which now makes up most of the truck route for the I-5 / SR-14 interchange.

Even with the improvements and modernization, US 99 still could not accommodate all the traffic traveling on it. In 1947 the section of US 99 from downtown Los Angeles to the Oregon border was designated as a part of the Interstate route that would later be known as I-5. However, no real consideration for upgrading US 99 to Interstate standard occurred until 1956 with the passage of the Interstate Highway Act, giving a funding mechanism to the 1947 Act. In the late 1950s plans were drafted for converting US 99 into an eight lane Interstate superhighway. The end was near for US 99 after 40 years of service.

Interstate 5

Between 1960 and 1967, I-5 replaced all of old US 99. I-5 through the Tehachipis proved a major public works project - one of the most impressive in all of the Interstate Highway system. As testament to this, more dirt was moved to grade for it than was used for the entire Aswan High Dam in Egypt and it is one of the few single man made objects that can be seen clearly from space. The first section of I-5 was completed from Tejon Summit to Grapevine at the foot of the San Joaquin Valley in 1960. Various sections of US 99 were bypassed and paved over by the new I-5. The last section of US 99, Weldon Canyon, was replaced by I-5 in 1972 and by the time that section was completed the last familiar and venerable US 99 shields were taken down. The complete the elimination of old US 99 in the area was symbolized by a large portion through Piru Gorge being submerged under Pyramid Lake in 1970. Ironically, it was consideration of placing a reservoir in this canyon 60 years earlier that prompted the far more difficult construction of the Ridge Route, rather than following the safer and easier course along Piru Creek. Despite this, there are many remaining sections of the first three alignments that are rather easily accessible from I-5.

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Weldon and Gavin Canyons

This portion of the tour covers the "Newhall Bypass," the section of old US 99 that bypassed the towns of Newhall and Saugus in 1928 by way of Weldon Canyon. Not only was this one of the first sections to be built as US 99, but this section, which went from the junction with US 6 to the foot of the Santa Clarita Valley over Weldon Summit was one of the most difficult to build. While the mountains in this area may seem rather insignificant as the two modern superhighways, I-5 and SR-14 traverse them with ease, they have always posed a major obstacle to road builders. The first paths over these mountains were Indian trails, but with the arrival of the Europeans, they soon became the major route for getting into Los Angeles. The Emigrant and Midland trails went along this route and were the first instance of major construction in the area. The first major cut, which is visible about 1/2 mile north of the present I-5/SR-14 interchange was made under the auspices of General Phineas Banning and later widened by General Edward F. Beale. This cut permitted wagons to traverse the mountains with more ease and even accommodated cars until the construction of the Newhall Tunnel in 1910. It was a narrow, one-way tunnel and was daylighted in 1938 to accommodate the ever increasing vehicle traffic. The site of the tunnel is located at a massive cut along Sierra Highway, which was again widened in 1968.

Before 1930, US 99, which incorporated the Ridge Route, followed the general route of Sierra Highway to its intersection with the "northern" San Fernando Road. Today, it is difficult imagine how these mountains were a major barrier to road construction, but it is important to bear in mind how significantly the construction of the two freeways altered them. Building a road which would provide more direct routing for US 99 was not possible until the late 1920s, when both road building technology and funding had sufficiently advanced to permit it. The Weldon Canyon bypass (officially known as the "Newhall Alternate"), which is now covered by I-5, was completed in 1930 and offered a substantial saving of time as well as increasing safety. Until its widening in 1951, this road was three lanes, with the suicide lane in the middle.

1958 ACSC Mapf of Golden State Freeway The I-5/SR-14 interchange marks the site of the US 99 and US 6 split. US 99, of course, continued north and US 6 continued its transcontinental journey to Cape Cod, MA. Like the rest of US 99, this interchange has gone through several incarnations. Prior to 1928, there was, of course, no interchange here. US 99, which followed the present San Fernando Road, then made a sharp jog to the east, crossing over the railroad tracks over the same viaduct that stands today. Originally built in 1910, this viaduct was widened in 1938 and has remained unchanged since. Upon the completion of the Weldon Canyon bypass, this viaduct no longer carried US 99, but in 1934 it became part of SR-7, later US 6.

The next major improvement to this interchange was the construction of the US 99 freeway in 1954. This was a very major improvement as it made it a true freeway to freeway interchange with three levels that directly connected US 6 south to US 99 south and US 99 north to US 6 north. About half a mile to the north, the freeway merged back into the original road. Although it has been modified, the original US 99 freeway is still visible as the present I-5/SR-14 truck route. Ironically, it has withstood two major earthquakes that its successor interchange did not: the 1971 Sylmar and the 1994 Northridge quakes. The US 99 bridges were modified in 1971 and 1994, but still resemble the original freeway. Unfortunately, the tunnel connecting US 6 to US 99 south was filled in 1971, but is still visible.

Mike Ballard has several historical photographs from the 1950s of the US 99/US 6 interchange. Slow links beware of extended download time.

"Looking northerly along Weldon Canyon
section of Ridge Route toward Weldon
Summit." (1953)

North of the US 6 interchange, US 99 entered Weldon Canyon. Weldon Canyon is a stark contrast to the barren mountains that surround it and even though much of it has been paved over by present I-5, the lush vegetation that dotted its hillsides is still visible. Before 1928, this was a steep canyon, filled with vegetation reminiscent of someplace in the Pacific Northwest. The first road to cross it was only three lanes wide and hugged the western wall. It was widened into a four lane divided highway by 1953, but generally followed the previous alignment, which was engineered well enough to be incorporated into the newer highway. In fact, much of the widening work done in the 1940s and 1950s used the older alignments as half of the divided and widened road. The section between the I-5/SR-14 interchange and Lyons Ave was one of the last sections of US 99 to be replaced by I-5, having been bypassed between 1967 and 1972. Much of this highway still exists and is known today as "The Old Road" (don't mention this name to Highway 99 fans!) This may be reached by following San Fernando Road beyond the intersection with Sierra Highway. At the top of Weldon Summit, the 1953 alignment appears from under I-5 and joins "The Old Road."  For a brief time after the 1994 Northridge quake, this section once again served as the major artery to northern California since several bridges had collapsed on I-5. Consequently, it was modified by having the original concrete paved over and by the addition of a concrete median barrier. Aside from these changes, the road appears as it did in 1953.

I-5 crosses over The Old Road at the bottom of Gavin Canyon on two tall viaducts. These had collapsed in 1994, which was the cause of its brief time as the I-5 detour. The divided road continues to just shy of I-5 and Calgrove Blvd. North of here, it was covered by the I-5 alignment to about 1/2 mile south of Magic Mountain Parkway. It possible to see, just to the north of the Calgrove Blvd. interchange with I-5, where the 1930/1951 lanes go under the freeway. While the frontage road to the west of I-5 is signed as "The Old Road", it is not as the real Old Road is now buried under the southbound lanes of I-5. Evidence that this is the case can be found by looking for one of the old culverts now used by I-5 dated 1929.

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Santa Clarita Valley

US 99 descended into the Santa Clarita Valley after negotiating Weldon and Gavin Canyons. Before the days of

Exit I-5 at Valencia Ave and head to the west (left from I-5 if heading northbound) to reunite with old 99. It makes a sharp right turn, then becomes divided. It is very apparent were the old divided road merges in, out from under I-5. With the exception that the concrete has been overlaid with asphalt, the road looks exactly the same as it did before it was bypassed by I-5 in 1964. Magic Mountain Parkway used to be called Saugus Ventura Road and the intersection was modified with the construction of I-5 so it is slightly to the south of the original interchange. This point marks about where the pre-1930 alignment of US 99 reunites with the later ones.

Santa Clara River and Disaster

"The Old Road" crosses the usually bone dry bed of the Santa Clara River over a bridge built in 1928. Interestingly, the bridge has remained unchanged since then and the ornamental guardrail on the one side looks the same as other bridges built during this time. At first glance, the Santa Clara River may seem little more than a piddling stream with inappropriately large bridges crossing it. However, like many other southern California rivers, it can pack a wallop of a flood, albeit for a brief time. Ironically, the Santa Clara caused its worst recorded damage, not as the result of Mother Nature, but as the result of a man made calamity: the collapse of the Saint Francis Dam. Many things happened that testify to the damage this one event caused. Before the collapse, there was a bridge located about 100 yards to the west that had previously carried the Ridge Route, but it had been completely wiped out by the flood waters. Today only the embankments and two piers remain of the bridge and they are only fit to ignominiously carry several utility pipelines. The collapse and subsequent flood was one of the worst peace time disasters in American history causing the deaths of 450 people and wiping out almost everything near the Santa Clara River. It also ruined the reputation (and deservedly so) of William Mulholland, Los Angeles' water guru, who is purported to have stated, "I envy the dead."

It appears the Santa Clara River will once again claim more casualties. These are the 1928 US 99 bridge and, surprisingly, the 1964 I-5 bridges. The reason is because none of these bridges are on solid footing and would certainly collapse during an earthquake since the riverbed below them would liquefy. For several million years the river has been taking sediment away from the rapidly decaying San Gabriel Mountains, creating a bed that is now over 200' above bedrock. This is the depth the footings for the new bridges will need to go in order to be seismically sound.

Castaic Junction

Castaic Junction is the next major feature to the north. The current incarnation, located about one block to the east, is the intersection of I-5 and SR-126, west. Previously, it had been the intersection of US 99 and SR-126; SR-126 is almost as old as US 99, having been a part of the original California System since its inception in 1934. Even though there is barely anything left to show it, this was once a thriving intersection which was home to Tips Restaurant and one of the largest Standard Oil stations. A little fun fact, according to Mike Ballard is that Tip's Restaurant was the last place James Dean ate before his tragic crash on US 466 (SR-46), another historic highway. The roads themselves have remained essentially unchanged, with all the original curbs that date back to the 1949 widening.

North of Castaic Junction, The Old Road narrows down to two lanes since I-5 now covers what were once the northbound lanes. In a way this is ironic since the former southbound lanes were part of the 1933 alignment; the northbound lanes were added later. It crosses Castaic Creek over a bridge built in 1931 with characteristic concrete arch guardrails. Old US 99 once again disappears under I-5, but emerges shortly before the Lake Hughes Rd. interchange. The road that emerges is the 1933 alignment only; in 1951 the US 99 expressway bypassed the town of Castaic and is now under I-5.

Castaic: Start of the Old Ridge Route

Castaic dates back from the days of the Ridge Route when it was a major stop; even today it is still an important truck stop. It marks the divergence of the original Ridge Route and the 1933 Ridge Route Alternate. Until recently, the Ridge Route had retained its original concrete, but as part of the ongoing construction in the area, it was overlaid by a new asphalt layer. In fact, a major portion has been wiped out to make way for even more houses. Within the town, there are several aging buildings which undoubtedly date back to before the 1940s. The three lane concrete road goes north out of Castaic to reunite with I-5 going up Five Mile Grade along a very well preserved section. The concrete surface is still exposed and there is a bridge that was built in 1930 that also remains perfectly preserved. I-5 is the only way to get to Five Mile Grade and the rest of old US 99. It can be reached by backtracking to Lake Hughes Road.

Side Trip: The Old Ridge Route

Much of the old Ridge Route remains, appearing almost exactly the same as it did when it was supplanted by the Ridge Route Alternate in 1933-34. The tour covers the portion remaining between Castaic and Gorman.

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Five Mile Grade and Whitaker Summit

Five Mile Grade is one of the most treacherous sections of US 99 and has been the site of many accidents as well as blown radiators from overheating. As the names implies, this grade is five miles long. Since its opening, it has gone through three incarnations, each a significant improvement of the previous one. Initially it opened in 1933 as a three lane "superhighway" which was a vast improvement over its predecessor, the steep and windy Ridge Route. Even with the improvements, it was still incredibly steep and long grade, especially for those going down hill. In 1948, it was widened, this time to four lanes. While it did improve safety by eliminating the dubious suicide lane and allowing for passing, it gained a wicked reputation for having a high accident rate. This was due largely to the ever increasing traffic. Trucks would often lose their brakes going down the grade and the result was often tragic. Even the addition of a truck escape ramp failed to eliminate the accidents. It is still visible about halfway up the grade and incongruously faces south where today there is only northbound traffic.

In 1970 the unique configuration of I-5 was completed and it has since improved the safety of this section considerably. US 99 was converted into the northbound lanes of I-5 and brand new southbound lanes were added on the other side of Violin Canyon. The new southbound lanes were built with a gentler and more even slope and follow a straighter alignment. This has prevented many runaway trucks as well as eliminating head-on collisions due to the wide separation (up to 1000') between the two sides. In order for this configuration to be possible, the northbound and southbound sides of I-5 needed to be switched, which creates curiosity of seeing traffic flowing in the opposite direction on the right rather than left side. Fun fact: the two bridges where I-5 crosses itself are called the Route 5/5 Separation in the Caltrans Bridge Log. Many people mistakenly identify this as the Grapevine since the road is windy and crosses itself, just as the branches of a grapevine would. The real Grapevine is located 40 miles to the north and will be covered later in this tour.

99-big_oak_flat.gif (10880 bytes)

Big Oak Flat (Templin Highway exit)

Just beyond the north Route 5/5 separation (that just sounds too cool!), the northbound lanes diverge from the original routing of US 99, veering to the left and reunite with the southbound lanes. While the pavement was removed upon the completion of I-5, the grading is still very visible. The old alignment crosses under I-5 and emerges about 100 feet south of Templin Highway. It remains separate from I-5 for the next 22 miles to the north until Smoky Bear Road. This section is commonly known as Violin Summit, but that name is a misnomer since the true summit is Whitaker Summit, one mile to the north. This summit does mark the end of Five Mile Grade where US 99 goes along the flat area called Big Oak Flat. An aerial photograph of Violin Summit is available, taken in 1994. (Be warned of the ~110 kilobyte download). This section can be reached by exiting I-5 at Templin Highway, then turning left. The section near Templin Highway is signed "Golden State Hwy." and is beautifully preserved. It is divided for about 1/4 mile and then goes back to four lanes undivided. This section was widened to four lanes in 1949, completely obliterating any traces of the former 1933 section. It then reaches Whitaker Summit, which marks the top of Three Mile Grade.

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Three Mile Grade and Piru Gorge

US 99 is almost entirely preserved between Whitaker Summit and Pyramid Lake and dam, although portions have not aged well. This section was  relinquished by the Caltrans in 1997 and reverted to Los Angeles County. As a result, it was repaired, but to save money it was made into a two lane road since landslides have claimed many parts. Three Mile Grade descends into (or ascends from) the Piru Creek Gorge and ends at Frenchman's Flat, a popular fishing spot, both in the days of US 99 and today. Part of the old road has been turned into a parking lot and a gate prevents any unauthorized vehicular traffic from entering the next section. The road continues about two miles beyond the gate to the base of the dam, but it is now only accessible by foot or bicycle. However, it is worth the trip.

The section of US 99 beyond the gate was closed off to vehicular traffic in the late 1980s. It has been a dead end since 1970 when it was blocked by the construction of Pyramid Lake and dam, a significant reservoir for the State Water Project water headed for the Los Angeles metropolitan area. Apparently the portion to the north of the dam was submerged intact and likely will see the light of day again. The road is very well preserved beyond the gate and looks exactly the same as the road going down Three Mile Grade once did. Basically it was a standard four lane road with a set of double white (later yellow) lines paved with asphalt. The 1933 alignment, which was paved with concrete, was buried under the 1951 widening and is visible only in a few places. There is a bridge about 1/2 mile beyond the gate which is the only one remaining that was part of US 99 and not modified by the construction of I-5.

Side Trip: Piru Gorge and Pyramid Rock

Hike or bike to see old 99 through the scenic Piru Gorge and the famous Pyramid Rock. Also features a remaining bridge that was built in 1933 and widened in 1951.

Beyond the dam, about 10 miles of US 99 lie submerged beneath the lake. It is a real shame since by all accounts, this was the most scenic stretch of US 99, passing through a narrow gorge and crossing the creek several times. The lake was placed here since this narrow gorge is an ideal place to hold water. This section was originally built as three lanes and widened to four lanes divided in 1951. The road itself resembled the section of road leading up to the dam, but further north as the gorge widened out, there was a scenic divided portion. Some of that is visible north of Pyramid Lake, which will be covered in the next section.

Mike Ballard has a historical photograph of the highway through here taken shortly after the completion of the highway in 1933.

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Pyramid Lake to Gorman

The next visible portion of old US 99 is accessible from the Smoky Bear Rd (formerly Hungry Valley Rd) exit from I-5. Head to the left (west) on Smoky Bear Rd to the intersection with US 99. To the left is a fairly pristine section of the divided highway, which looks much the same as it did during its heyday, although further down only the southbound lanes remain since the northbound lanes were taken out to make way for the California Aqueduct. The road continues to near the shore of Pyramid Lake, but to get to it requires paying an entrance fee at the gate. Although I personally have not seen US 99 beyond the gate, I am told it is not worth the money to get in. Beyond the gate, the original US 99 roadway was taken out and replaced by an imposter concrete divided road. Backtrack on US 99 to beyond Smoky Bear Rd. Again, this is a part of the divided highway from the 1949 widening. It is covered by I-5 about 1/4 mile north of Smoky Bear Rd; I-5 covers the original grade of US 99 for the next six miles to the intersection with SR-138.

SR-138 is an ancient road in California highway terms since it was one of the first state sign routes commissioned in 1934. Its original interchange with US 99 was several miles to the north, in the town of Gorman. With the construction of I-5 came dreams that it would be built as the so-called "Metropolitan Bypass Freeway," an idea that never came to fruition. The only section that was built was the sizable I-5/SR-138 interchange, which now has the dubious distinction of being (especially with the demise of SR-480 in San Francisco) one of the "World's Longest Off-ramps."

Side Trip: Ridge Route to Gorman

See a perfectly preserved section of the old Ridge Route and follow the original alignment through Gorman.


99-gorman_overview.gif (12626 bytes)


Gorman marks where all three incarnations of US 99 met again. The map at left shows where two of the three may be found; the 1951 expressway is located beneath I-5. The Gorman side trip includes the detail map outlined at left.

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99_old_shield.gif (3823 bytes) North: Tejon Summit and Grapevine
South: San Fernando Valley


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