Category Archives: History

Image of the Week – 6/6/15

Sidewalk dating to May 1897 on Fifth Ave between Nutmeg St and Olive St in San Diego, CA.
Sidewalk dating to August 1897 on Fifth Ave between Nutmeg St and Olive St in San Diego, CA.

Finding Old Highways – A Guide – Part 2

Concrete Paving

Concrete is a very durable material. It has many uses, though for our purposes – roadway surfaces, curbs, and sidewalks. Local roadways, such as concrete city streets, won’t be covered in this post. Bridges will be covered in a later post. This durability allows us to get either a relative date of when a roadway was paved or built to an absolute date when we find a date stamp.

  • Style of Paving
Short section of Roberts Rd that is now a driveway.
Short section of Roberts Rd that is now a driveway.
1920's paving near Osborne St. Note the widening work that was done on the right side. Looking west.
1920’s paving near Osborne St. Note the widening work that was done on the right side. Looking west.

As technology has evolved, so has concrete paving. The first concrete paving along State Highways was 10-12′ wide, usually not reinforced with steel. These roads were paved in one single slab of concrete. Roadways of this style were paved from around 1910 to 1915. After 1915, wider paving was used and was generally reinforced. Wider paving ran from 15′, 18′, and a “full” 20′. These are usually referred to as “Single Slab Paving”.

Sometime around 1923, longitudinal joints were added to the concrete paving. This created a “Twin Slab” roadway. This style persists today, though greatly changed. Early Twin Slab roadways had fewer expansion joints running across the lane. After around 1926, this problem was worked out by adding more frequent joints. By this time, each lane was a “standard” 10′. This standard remained until the late 1940’s when lane width started to widen to 12′.

  • Date Stamps
1948 date stamp on Olympic Blvd.
1948 date stamp on Olympic Blvd.

Contractors, either by requirement or pride, usually stamp the concrete roadway, curb, or sidewalk with a date stamp. These stamps vary in location, size, and information. Date stamps marked either the beginning or end of a days paving. As such, the stamp tended to be located near an expansion joint. A general rule with date stamps is “find one, you can find the rest”. This is mostly about the location. Some stamps are in the middle of a lane, some are to the side of a lane. The orientation also varies with stamps. The information contained in these stamps also varies. Early stamps just have the contractor and the date. Later stamps added the engineering station. Without going into too much detail, at this time, about engineering stations, the “zero” point is at the beginning of a road section or project. With little exception, I have had little success in finding a date stamp on Single Slab roadways. Twin Slab roadways are much better with stamps.

Using date stamps and styles as a guide, you can easily date a roadways construction to within a few years. There are other methods you can use, but these aren’t covered here. Some will be covered in later posts. Stay tuned for more posts. Bridges, Road Signs, and more will be covered in the future. If you have any questions, please post a comment or send me a message.

Finding Old Highways – A Guide – Part 1

When looking for old highways, there are many clues you can use to help discover where old highways ran. This will serve as a partial guide to finding those clues and figuring out the history of a roadway in California.

State Highways

When you are looking for clues if a roadway you are on is an old State Highway, there are a few things to look out for. Depending on the age and location, look out for Right of Way monuments. In California, these are small concrete blocks with a C on the side of them, facing the roadway. They tend to be at the fence line along roadways, at the same distance as the utility poles, or further out. How much they stick out also varies. Some are just a few inches above the ground where others are about a foot high. Look out for these monuments at the beginning or ending of a curve usually about 50-100′ from the centerline of the roadway (or former centerline).

Old C-Block State Highway Right Of Way marker from 1930.
Old C-Monument State Highway Right Of Way marker from 1930.

Other clues tend to be tougher to spot but can be very subtle in appearance. Roadways that were formerly paved with concrete instead of asphalt are usually cracked in a very specific way if the asphalt is old enough. Expansion joints in the concrete, potholes exposing the old paving, or a defined crack running near the roadway edge usually give this away. Older concrete paving was either 15′, 18′, or 20′ wide. Modern roadways are usually 24′ wide, with two 12′ lanes. Look out for this concrete at curves which appear to have been straightened.

Original alignment of the Ridge Route at Tejon Pass. These lanes were built in 1923 on top of the original 1919 Ridge Route concrete.
Original alignment of the Ridge Route at Tejon Pass. These lanes were built in 1923 on top of the original 1919 Ridge Route concrete.

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On some roadways bypassed or abandoned after 1964, old postmile markers can be found. These markers are similar to the ones on current State Highways. On a current roadway with R mileage, look for old alignments in the area. R mileage indicates a realignment that took place after 1964, which is the point of “base mileage” for California State Highways.

This milepost was found near Whitaker Summit on old US 99. US 99 was gone legislatively in 1964 so Route 5 took over the numbering here. That is why it shows the mileage for I-5.
This milepost was found near Whitaker Summit on old US 99. US 99 was gone legislatively in 1964 so Route 5 took over the numbering here. That is why it shows the mileage for I-5.

Abandoned roadways are tougher to spot depending on the area climate. Drier climates tend to preserve older paving better than wetter climates. In some areas, the paving itself was removed after the roadway was bypassed. I have found a few sections of roadway relatively intact, complete with old striping, in Central and Eastern California. When the pavement has disintegrated or obliterated, you can look out for areas where there is less vegetation and distinct roadway grade. Sometimes old drainage culverts and bridges are left behind with nothing but dirt grade leading to them.

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More paving, both lanes now visible.
More paving, both lanes now visible.

In any area, make sure to take plenty of photos if you find an old alignment. You never really know when the local jurisdiction will come along and either obliterate or repave the roadway. This is fairly common in Los Angeles County as I have found. The most recent loss has been the June 1933 three lane concrete in Gorman along old US 99 which was repaved in the past couple years. Document what you find as best as you can. Doing so will help to preserve the memory of these forgotten roadways for many years to come.

Image of the Week – 3/15/15

Interstate 5 under construction at Magic Mountain Parkway in 1964.
Interstate 5 under construction at Magic Mountain Parkway and the Santa Clara River in 1964. Old US 99 is visible on the right side.

Image of the Week – 3/9/15

St. Francis Dam site in 2006 from the reservoir side. The crumbling remains of the wing dam are visible on the ridge to the right.
St. Francis Dam site in 2006 from the reservoir side. The crumbling remains of the wing dam are visible on the ridge to the right.

March 12, 2015 will mark the 87th anniversary of the collapse of the St Francis Dam in San Francisquito Canyon, Los Angeles County, California. The collapse occurred just before midnight on March 12, 1928. It is still California’s second largest disaster in terms of lives lost. Approximately 500 people died in the ensuing flood which flowed to the ocean near Oxnard, CA along the Santa Clara River Valley. Only the 1906 San Francisco Earthquake and Fire exceeds the number.

Road Building in San Gabriel Canyon

In the 1930’s, Los Angeles County began construction of an additional roadway over the San Gabriel Mountains via the East Fork of the San Gabriel River. About half of the roadway, complete with with four larger bridges and a tunnel, was constructed. Work had progressed as far as “The Narrows” by 1938. However, the March 2-3, 1938 storms caused much of the roadway to be washed out. The project was then abandoned, leaving a large arch bridge stranded many miles upriver. The tunnel still exists as well, just north of the “Bridge to Nowhere”, though it has been sealed at both ends.

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1936 arch bridge – The Bridge to Nowhere
1936 stamp on the arch bridge.
1936 stamp on the arch bridge.
Looking over the arch bridge to the tunnel site.
Looking over the arch bridge to the tunnel site.
Abandoned and partly destroyed bridge over the river.
Abandoned and partly destroyed bridge over the river.
Bridge over Cattle Canyon on the East Fork Road. This is similar to what the removed bridges north of here would have looked like.
Bridge over Cattle Canyon on the East Fork Road. This is similar to what the removed bridges north of here would have looked like.
1934 USGS Camp Bonita map showing the roadway completed to about 1 mile south of the “Bridge to Nowhere” site.
1940 USGS Camp Bonita map showing the now stranded bridge location.

In the 1955,  a new road building project commenced in the canyon. This new alignment would stay high above the canyon floor until it got nearer to the “Bridge to Nowhere”, allowing that earlier work to come to some use. Progress on this roadway was slow, mostly due to poor funding. Convict labor was used for most of the project, similar to many other road building efforts at the time in Los Angeles County. Two tunnels were constructed as well. These still exist and are mostly intact. This project too was cancelled in the late 1960’s, leaving another large scar in the canyon. This road is presently known as Shoemaker Canyon Road.

Stone railing along Shoemaker Canyon Road.
Stone railing along Shoemaker Canyon Road.
Looking toward the higher peaks of the San Gabriels along Shoemaker Canyon Road.
End of the pavement and open section of Shoemaker Canyon Road.
End of the pavement and open section of Shoemaker Canyon Road.
1961 and 1964 tunnels in view.
Partly graded roadway and tunnel along the "Road to Nowhere".
Partly graded roadway and tunnel along the “Road to Nowhere”.
Date stamp on the first tunnel.
Inside the longest tunnel, from 1961.
Grading along the "Road to Nowhere".
Grading along the “Road to Nowhere”.
Northern tunnel from 1964.
Northern tunnel from 1964.
1966 USGS Glendora map showing the “Shoemaker Canyon” roadway under construction.

Today, the canyon is protected from future development through the Sheep Mountain Wilderness Area. Even without this protection, the geology of the canyon makes for a very expensive project. Maintenance would also be costly, as seen with State 39 through San Gabriel Canyon and above Crystal Lake. In time, all these structures and cuts will wash away, leaving the canyon with only bits of concrete and asphalt to show what was once here.

Remnants of paving in the canyon.
Remnants of paving in the canyon.