HISTORY121 - Road Signs

Recently Pat and I were driving down a local road in Tucson, and Pat said something about wanting to know more about road signs, e.g., their history, how they were manufactured, how the government fits in, and more.  So, once again, I thank Pat for identifying a good blog topic.

 

After a short introduction, I will talk about the earliest road signs, from Ancient Rome to the 17^th century, the early influence of bicycles and automobiles, standardization of road signs, modernization and expansion of road signs, how road signs are made today, the digital age of road signs, advertising road signs, and finally, the future of road signs.

As usual I will list my principal sources at the end.

 

Introduction

For the purpose of this blog, I define road signs as signs erected at the side, or above roads, to give instructions or provide information to road users.  Typically, the purpose of road signs is to manage vehicle traffic or to provide advertisements.

Traffic sign history stretches across centuries, evolving alongside human civilization and transportation technology, from simple location-defining sign posts to a myriad of static (one message) traffic control signs, and from those to artificial-intelligence-powered, variable message digital signs.  With over 164,000 miles of highway and, four million miles of public roads in the United States, traffic signs are a necessity in today’s world.

The history of advertising road signs dates back to ancient civilizations, but modern billboards evolved with mass printing and the widespread use of automobiles.  Over time, technology has transformed roadside signs from hand-painted advertisements to dynamic, digital displays that can be interactive and animated. 

 

Earliest Road Signs

Romans. The history of road signs starts with the history of the first roads.  The Roman Empire was the first civilization to construct roads.  By building a system of roads, tunnels, and bridges across the vast Roman Empire, the Romans were able to move armies faster and bring in more people and goods.  In other words, a strong road system helped Rome thrive.

The first road was the Via Appia, or the Appian Way, built in 312 B.C.  At the peak of Rome's development, no fewer than 29 great military highways radiated from Rome, and the Empire's 113 provinces were interconnected by 372 great roads. There were more than 250,000 miles of roads, of which over 50,000 miles were stone-paved.

To help travelers navigate, the Romans installed milestones - cylindrical stone columns engraved with information such as the distance from Rome, the distance to the next major city, and the name of the reigning emperor.

The columns were made of granite, marble or whatever local stone was available.  Each measured between 6.6 to 13.1 feet high, with a diameter of 19.5 to 31.5 inches, and were placed at approximately one-mile intervals.  Based on the road network's length, historians estimate that hundreds of thousands of milestones existed throughout the Roman Empire. 

Example of Roman milestone, engraved in Latin.

 

In ancient Rome, people traveled by horseback, in carts pulled by oxen, or by walking - there wasn’t yet a need for complex highway sign systems to accommodate heavy traffic.  That came later.

While these milestones didn’t control traffic, they were vital in organizing travel across a sprawling empire.

Middle Ages to 17^th Century. After the fall of Rome in 476 AD, Roman road systems were still in use, although not maintained.

By the 17^th century, in Europe, multi-directional signs were being placed at crossroads to direct or point people toward different towns.  In England, these were known as "fingerposts.”  Roads were being named after the towns they led to.  In 1648, a law in Britain required each parish to construct guide posts.

Example of English fingerpost road sign.

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Since most of the population was illiterate, businesses used pictorial signs to identify their services, such as barbershops (bloody bandages for the surgery and dentistry service they performed then), apothecaries (mortar and pestle), taverns and inns (crown or coat of arms), and butchers (animal head, cleavers, or hatchets).  These “advertising” signs were often highly ornate and designed to be visible from a distance. 

People still traveled either in a covered wagon, on horseback, or by foot.  However, transporting goods in wagons slowed down horses and made travel a slow process.  It wasn’t until travel became faster, with the invention of the bicycle and the automobile, that a need for better road signs developed.

 

 

Early Influence of Bicycles, Automobiles

Bicycles. The first modern road signs erected on a wide scale were designed for riders of bicycles in the late 1870s and early 1880s. Bicycles were fast, silent, and their nature made them difficult to control; moreover, their riders travelled considerable distances and often preferred to tour on unfamiliar roads. 

By the end of the 19^th century, cycling organizations began to erect cast iron signs that warned of potential hazards ahead (particularly steep hills), rather than merely giving distance or directions to places, thereby broadening the use of road signs. 

Automobiles. The development of automobiles in the early 1900s encouraged additional signage systems that provided navigational assistance, and hazard warnings, and the beginning of traffic control.  Also, advertising road signs began in earnest.

Note: The American Automobile Association (AAA) was founded on March 4, 1902, in Chicago, Illinois, in response to a lack of roads and highways suitable for automobiles.

The first road signs in the U.S. were erected by the AAA.  Starting in 1906, regional AAA clubs began paying for and installing wooden signs on iron columns, to help motorists find their way.  In 1914, AAA started a cohesive transcontinental signage project, installing more than 4,000 signs in one stretch between Los Angeles and Kansas City alone.  

Note:  At this point in history, road signs were focused on navigation and hazard warning, not traffic control.  Vehicles operated at low speeds, and drivers were expected to watch out for other vehicles and obstacles.   Also, in the early 1900s the roadways were still very rural and rough.  Road maintenance and signage was left up to local automobile clubs, who started installing their own wooden and iron signs to guide motorists. This led to confusion, with multiple different signs often placed at a single intersection.

Two innovations started traffic control on its long development path.  In 1914, a two-color (red and green) electric traffic light was installed in Cleveland, Ohio. Detroit police officer William Potts added the third, yellow "caution" light in 1920.  In 1915, Detroit installed the first stop sign, which was a small rectangular two-by-two-foot sheet of metal, with black lettering spelling “STOP” on a white background. 

Recreation of the first U.S stop sign in Detroit, Michigan in 1915

 

Automobile traffic began to increase in the 1920s, when cars became less expensive because they were being manufactured more efficiently on assembly lines.  Roads, once dominated by pedestrians, horses, and bicycles, now had to accommodate faster, heavier, and more dangerous vehicles.  People were traveling on roads they were not familiar with, and they were not being warned about potential hazards.  It was time for better, standardized road traffic control road signs. 

 

Standardization (1920s - 1940s)

It wasn’t until the 1920s, when various state governments stepped in, that street signs began to gain some clarity and standardization.   A series of reports from those states on improvements that could be made was published in 1927.  This was the beginning of street sign standardization in the U.S.

In 1935, the first edition of the Manual on Uniform Traffic Control Devices (MUTCD) was published by a joint committee of the American Association of State Highway Officials and the National Council of State Highway Officials, responding to a critical need for standardized traffic signs, signals, and markings across the nation.  

This original manual laid the foundation for the continuous evolution of the MUTCD, which has been administered by the Federal Highway Administration since 1971, and remains the national standard for traffic control devices on all public roadways. 

The first edition of the MUTCD consolidated previous standards for signs, signals, and markings into a single national document and established three main sign classifications still in use today:

·         Regulatory signs (e.g., speed limits)

·         Warning signs (e.g., curves and hazards)

·         Guide signs (e.g., directional information)

The original 1935 MUTCD also established distinct shapes for standardized road signs:

·         Round:  Warned of an approaching railroad crossing, considered a high-danger situation. 

·         Octagon:  Indicated the need to STOP, signifying the next level of danger at intersections. 

·        Diamond:  Signified more ordinary conditions requiring caution, serving as warning signs for curves, hazards, or other conditions needing driver awareness. 

·         Rectangular:  Provided regulatory information or directional guidance. 

·         Equilateral Triangle:  Alerted drivers to give way to other traffic. 

All signs still used block lettering, which had been standard for many years.  The minimum size for signs in this manual was 24 inches, and increased in size in six-inch increments. 

Note:  Other shapes, like U.S. Route Shields, and trapezoids for recreational and cultural interest areas. were establish later.

A revision to the MUTCD in 1939 required reflective elements on road signs to increase visibility at night. 

Modernization and Expansion (1950s - present)

The Federal-Aid Highway Act of 1956 launched the Interstate Highway System, necessitating new types of signs designed for high-speed, limited-access roads.

In the 1950s, the octagonal STOP sign was standardized with white lettering on a red background. 

Other uniform color standards were established for specific purposes:

·         Orange: Became the standard for construction and work zones in the 1971 edition of the MUTCD.

·         Yellow lines: The use of yellow centerlines to divide opposing traffic was adopted in the 1970s.

It wasn’t until the 1950s that deer warning signs were taken seriously, though. Nevada was the first state to include a deer warning sign in their driver manual in 1953.  However, by the 1990s, 24 states included deer warning signs in their driver manuals.  Today, depending on where you are, you could also see warning signs for turtles, elk. moose, or ducks. 

Inspired by European practices, the U.S. began adopting more universally understood pictorial symbols in the 1970sto improve driver comprehension.  This transition to symbols was driven by the goal of reaching non-English speakers and reducing the amount of reading time required at higher speeds.

Besides more symbols on road signs, the use of color evolved to indicate the message contained.  Here are present-day sign color meanings:

·         Red: Used to stop, yield, and prohibition

·         White background: regulatory sign

·         Yellow: general warning message

·         Green: permitted traffic movement and directional guidance

·         Fluorescent yellow or green: School or pedestrian crossings

·         Orange: Warnings and guidance in construction zones

·         Blue: Road service, tourist information, or evacuation routes

·         Brown: Guidance to recreational or cultural interest sites

Collage of today’s static traffic management road traffic signs.

 

The MUTCD continues to evolve, incorporating new challenges and technologies, with regular updates to address issues like electric vehicle infrastructure and the growth of self-driving cars.

 

How Static Road Signs are Made Today

Today's static road signs are primarily made using one of two main methods: digital printing on reflective sheeting or a process involving a plotter to cut vinyl lettering that is applied to an aluminum blank.  Both methods begin with the sign's design on a computer, which is then transferred to a physically cut and prepared aluminum sheet. 

Digital Printing. The sign's design is sent to a large format digital printer that prints directly onto reflective sheeting, often using UV-curing ink that is dry and ready immediately after printing.  The printed reflective sheeting is then carefully applied to a prepared aluminum sign blank.  A roller is used to press the sheeting onto the aluminum, ensuring there are no air bubbles or wrinkles.  The edges of the sheeting are trimmed, and the sign is punched for mounting holes. 

Example of digital printing of traffic road signs.

 

Plotter-Cut Vinyl. A computer-aided design is sent to a machine called a plotter, which cuts the letters and shapes from a sheet of colored reflective vinyl.  The excess vinyl is "weeded" away, leaving just the letters on a clear transfer tape.  The transfer tape is applied to an aluminum sign blank, and a roller is used to ensure it sticks without bubbles.  The transfer tape is peeled off, leaving the lettering adhered to the

 

Digital Age (Late 20^th century to present)

In the late 20^th century, highways began incorporating electronic signs.  These signs display real-time information about traffic, weather, and construction zones. Today’s LED digital signs take it further, offering dynamic updates and integrating with smart traffic systems.    Sometimes digital road signs use humor to get the point across.

Digital road signs often use humor to make the point.

 

Technology has helped us make huge advances in road signs and traffic control.  Some of the most notable achievements include:

Traffic lights that use sensors to control the flow of cars more effectively.

Some cities use adaptive traffic control systems with Artificial Intelligence (AI) to monitor traffic flow and adjust signals autonomously. 

Real-time traffic incident warnings can be conveyed directly to vehicle navigation systems using inaudible signals carried via FM radio, 3G cellular data, and satellite broadcasts. 

Cars can pay tolls, and trucks pass safety screening checks, using video numberplate scanning, or RFID.

Yet another "medium" for transferring information ordinarily associated with visible signs is Remote Infrared Audible Signage, e.g., "talking signs" for print-handicapped (including blind/low-vision/illiterate) people.  These are infra-red transmitters serving the same purpose as the usual graphic signs when received by an appropriate device such as a hand-held receiver or one built into a cell phone.

 

Advertising Road Signs (Early 1900s to present)

The first recorded leasing of billboard space for advertising occurred in 1867. The industry grew rapidly, and by 1870, nearly 300 small sign-painting and bill-posting companies were in operation.  At the Paris Exposition in 1889, the 24-sheet billboard format (20 feet by 9 feet) was introduced and quickly became the industry standard. 

The availability of the Model T automobile in 1908 led to a massive increase in car travel, creating a large, audience for roadside advertisers.  By the 1920s, companies like Coca-Cola and Palmolive were launching national campaigns using billboards. 

From the 1920s to the 1960s, the Burma-Vita Company used a series of small, sequential signs with rhyming jingles and safety messages to entertain drivers and promote its brushless shaving cream.  The campaign became a pop culture icon but declined with the rise of the Interstate Highway System (IHS) and increased speeds.

Iconic Burma Shave signs on famous U.S. Route 66.

 

The creation of the Interstate Highway System in the 1950s opened up nearly 50,000 miles of new roads, providing advertisers with a massive number of new opportunities. This created a "golden age" for billboards, with many brands using creative, outlandish scenes to engage drivers. 

The rise of technology has led to digital billboards that feature multiple advertisers and can be updated remotely, reducing the need for manual installation.  Neon and illuminated signs also became widespread in the 20^th century.

Today, some billboards incorporate sensors, cameras, and augmented reality to create interactive and personalized experiences.

The outdoor advertising industry now uses more eco-friendly materials, including eco-plastics and solar-powered signs. 

 

Future

The future of road signs involves a transition from static objects and messages to dynamic, intelligent systems that communicate in real-time with drivers, autonomous vehicles, and traffic management centers. These changes are driven by the evolution of technology, especially the rise of connected vehicles and AI. 

As technology advances, expect traffic signs to remain visually simple but more legible at night and from further distances.  The point of traffic signs is not to distract drivers, but to communicate a message as quickly as possible at any hour of the day.  Signs will continue to be manufactured with a high priority on legibility and standards.

As autonomous vehicles become more common, traffic signs will evolve yet again.  Smart signs equipped with sensors and connected to vehicle networks will communicate directly with cars, providing information about speed limits, hazards, and road conditions. 

 

 

I thought that I would close with a couple of funny road signs:

Pat and I saw this helpful road sign in the Smokey Mountains.

 

 Sources

My principal sources include: “Traffic Sign,” Wikipedia.com; “History of Traffic Signs,” degemmill.com; “The History of Road Signs,” and “The History of Street Signs,” dombossign.com; “The History of Traffic Signs,” americansignandsignal.com; plus, numerous other online sources, including answers to queries using Google in AI Mode.