Category Archives: Guide

What is a “C-Monument”?

Roadways and their right-of-ways are marked in various ways. Originally, roadway rights-of-way were poorly marked, and as a result, changed quite a bit. These changes made travel sometimes rather confusing the roadway path may have changed before the map the traveler used changed. This sort of problem also cost the State quite a bit of money as they had to not only correct the problem, but also deal with the potential land costs of a new alignment.

Starting in 1914, the California Highway Commission came up with a plan to mark the right-of-way in a more permanent manner. Their solution – a “C-Monument”. While not the official name, which is simply “survey monument”, it aptly describes the marker. These monuments would be placed at the edge of the right-of-way at intervals along tangents (straightaways) and at curve points (BC and EC or Beginning of Curve and End of Curve). Optimally, these monuments would project about 6 inches above the ground with the C facing the roadway. At the top of the monument, a copper plug was placed to help guide surveyors.

Old C-Block State Highway Right Of Way marker from 1930.
C-Monument along a 1930’s alignment of US 6 in Red Rock Canyon.

The C-monument was actively placed and used for many years, though when it finally was out of use seemed to vary between districts. In San Diego County in District 11, for example, they were used along freeways constructed in the mid to late 1950’s. Los Angeles County, within District 7, seemed to stop using them sometime in the late 1930’s. Today, the monuments that remain are still valid survey monuments. While not placed anymore, Caltrans, as well as local agencies, still use them. As such, please do not disturb or collect them if they are still in place.  Finding them along a roadway also doesn’t automatically make it an old State Highway. Some counties also used these monuments as they were a part of the standard plans for any project that involved state or federal dollars.

Finding these monuments is actually quite simple. Typically, roadway rights-of-way ranged anywhere from 100′ to more than 300′. Find a curve in the roadway you are looking at and look for one on either side of the roadway about 50 to 150′ away from the centerline of the roadway. In mountainous areas, the uphill one tends to be easier to spot than the downhill side. Fence lines, power lines, and other similar features can be used to indicate the right-of-way edge. As they can still be used today as survey monuments, some are marked with paddles or other objects to make a surveyors job easier when locating them. Placer County uses a white “R/W” paddle. Caltrans District 9, at least in Inyo County, uses orange poles as location markers.

August 12, 2017 Cajon Pass Highway Tour – Updated

South end of Blue Cut showing fire damage.

On August 12, 2017, I will be hosting this websites first highway tour in the Cajon Pass area. This tour will cover the roadway from Verdemont to Cajon Summit. Some portions will have to be skipped, unfortunately, due to fire-related closures. The start of the tour has changed from the initial announcement. It will now begin at Devore, in front of Tony’s Diner at 18291 Cajon Blvd, San Bernardino, CA 92407 at 8 am. Please do not park in their parking lot. There is plenty of on-street and off-street parking in the area.

After a brief introduction, we plan to leave at about 8:30 am. The tour will stop at the following locations:

  • Verdemont (backtrack)
  • Cajon Blvd (at the freeway)
  • Kenwood Ave
  • Keenbrook
  • Blue Cut
  • Debris Cone Creek
  • Cajon Junction
  • Cajon Summit

Additional stops may be added if needed. I strongly recommend bringing water and snacks as there are few water/food stops along the route. Please RSVP if you plan to attend this tour. Again, we will be leaving the starting point no later than 8:30 am. Please RSVP no later than August 11 so that I can get a rough number of how many will attend. I look forward to seeing you out there!

US 6 Tour goes east!

It has been a while since I’ve added to my US 6 tour. For quite some time, it “only” went to Tonopah, Nevada. While that town makes for a good end point, it left quite a bit of very interesting and scenic highway out of the tour. US 6 across Nevada is one of the emptiest highways in the lower 48 states. It gives travelers and geologists alike a very good cross section of the Great Basin as well as a look at the mining past of Nevada. With that in mind, my US 6 tour now extends to the Utah / Nevada State Line, covering approximately 620 miles of roadway.

Take your time and enjoy the tour!

Virtual Tour of US 6 Introduction

Finding Old Highways – A Guide – Part 3 – Bridges

Bridges

Bridges and culverts can be great indicators of when a highway was built and by whom it was built. In California, there are a few different styles of railing which can be used to put a relative date on a particular bridge when they don’t have date stamps on them. Other indicators may be used when the bridge rail has been modified or even replaced by modern rail. Styling elements on the superstructure vary depending on age. Older bridges tend to be more ornate than more modern structures. This page will serve as a guide to these styles and help to increase understanding of what goes into the design of these bridges.

Continue reading Finding Old Highways – A Guide – Part 3 – Bridges

Website Updates

Over the past week or so, I’ve been working to add more content to the site. Not to avoid completing the existing pages either, just to fill in some gaps. Here are some of the updates:

  • New Website Feature – a new Discussion Forums feature has been added. It is an experiment, so we’ll see where it goes.
  • New SectionCivic Information – These pages give links to every incorporated city in Southern California and give a bit of information about each county as well. The links are finished, but the format is still being worked on.
  • New PageSeeking Old Highways – A while back I was working on putting up a guide to looking for old roads, bridges, and signs. It is still a work-in-progress, but has now been more given its own page in the Highways section.
  • Additional Historic Photos – Old photos of US 101 in the Los Angeles area have been added to the US 101 page.

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.