From The Late 1920s Until The Early 1950s, Stop Signs Were Not Red, But What Color?

From The Late 1920s Until The Early 1950s, Stop Signs Were Not Red, But What Color?

From the late 1920s until the early 1950s, stop signs were not red, but what color? Unbelievably, we are discussing the STOP sign. Today’s ubiquitous red, reflective, octagonal traffic sign did not always have these traditional features. 

This article examines the evolution of STOP sign designs and how manufacturing procedures and human factors (vision and perception) have influenced these developments.

From The Late 1920s Until The Early 1950s, Stop Signs Were Not Red, But What Color? | Get The Engines Going

In the early years of the automotive industry, the desire to increase one’s productivity in business and agricultural practices gave rise to the desire to acquire a car. 

A farmer with a horse and cart could only realistically go 10 to 15 miles each day. Farmers who lived farther out from the city were thus constrained in their ability to travel and do business. 

This technology only slightly expanded the mobility capability of the few farmers who had cars. 

For these lucky people, the net gain represented the capacity to sell to several markets, increasing economic potential and profitability.

The earliest traffic signs were created and disseminated by automobile clubs due in part to financial constraints. 

At numerous locations along the early roads, members would post notices to other drivers. Unsurprisingly, there was a lot of variance and safety issues since there was no clear guideline for design or placement.

The Justification For Shape Is Infinitely Irritable

The fact that a significant majority of American drivers had a low level of literacy was a major problem that the Bureau of Public Roads had to deal with (U.S. Department of Transportation). 

This required that traffic signs be made in a fashion that was clear to everyone, whether or not English words were used. 

At this early stage in the development of traffic sign design, elements like shape, size, and color were particularly significant.

The vehicle, however, gradually evolved into a financially realistic alternative for many families by the early 1920s because of improvements in automotive manufacturing efficiency (i.e., the assembly line) and material consistency. 

In fact, the Bureau of Public Roads acknowledged the increase in the popularity of automobiles and sought a remedy to the escalating safety concerns. Engineers experimented with several STOP sign designs.

The Mississippi Valley Association of State Highway Departments came to the conclusion that a sign’s “danger level” could be calculated based on its number of sides using nothing more than intuition and some input from train engineers. 

These engineers believed it to be common knowledge that the circle had the most sides—an unlimited number, in fact—of any solid shape. 

Then, circular traffic signs indicated the locations that posed the greatest threat to drivers. Consider for a second how absurd that choice was.

Circular signs have been utilized solely in railroad settings throughout time. The STOP sign’s octagonal design, however, continued to be associated with motorway environments.

In fact, Reforming Our Street Traffic Urgently Needed, a groundbreaking article produced for the journal Rider and Driver is credited with introducing the idea of traffic signs, according to the New York Times. 

The author’s straightforward request includes posting stop signs at intersections of streets. This request was made at a time in history when most roads were unmaintained gravel or dirt, had no line markings, and had no set speed limit.

No clear separation of pedestrian and motorist areas, and no traffic lights (the first traffic light in the United States wouldn’t be installed in Cleveland, Ohio, until 1914 by the American Traffic Signal Company).

The Justification For Color

After “resolving” the form problem, color was a consideration for STOP sign designers. Red had to be the favorite. 

Unfortunately, in important automobile hubs like Detroit, Michigan, the Bureau of Public Roads started manufacturing yellow STOP signs in 1915 (Moeur, 2010. 

Why yellow? The human eye is most effective at detecting colors in the yellow and green spectrum, particularly when scotopic vision (i.e., high use of rods, low use of cones) is utilized in low light, according to early.

Human Factors and physiological studies (e.g., dusk; night time). Contrary to popular opinion, red is neither immediately nor readily noticed in dim lighting. In fact, without artificial light, it is almost difficult to distinguish the hue red at night (e.g., backlighting, headlights).

By 1924, a uniform, the bright yellow hue was used to make all “warning”-style signs. To distinguish between the warning and instructional types of traffic signs, all other signs were given a white backdrop. 

The best degree of contrast (with black lettering) in low-light situations (such as at night, during a downpour, or in a fog) that manufacturing techniques could achieve at the time was offered by both of these lighter hues.

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However, Issues Remained

Despite their best efforts, the number of collisions and problems on the roads (which are degrading) kept rising from year to year. 

There were three main aspects to this problem: A higher level of power and speed was being built into cars, there were more drivers on the road, and headlights and streetlights were insufficient to illuminate STOP signs on their own.

At the time, headlamps barely lighted the area in front of the car for roughly 100 feet. Today, however, we know that taking into account typical brake response times, the normal (undistracted, unfatigued) driver moving at, say, 30 MPH, needs between 115 and 187 feet of stopping space. 

If drivers went more than 30 MPH, there simply wasn’t enough space for them to react to an unknown or unexpected STOP sign and behave accordingly.

It was necessary to improve the STOP sign’s visibility and brightness at this stage of its development.

Increasing Our Horizon

Experts took into account various design approaches. The use of glass “beads” in traffic signs was the one that first prevailed throughout the 1930s. 

The word “STOP” and a border of glass beads with a diameter of less than an inch adhered to the sign. These beads had a diffuse reflection component that improved vision at night while the driver’s headlights were on.

Diffuse reflection, in a contrast to mirror reflection, works by simultaneously dispersing a part of a light source in all directions. 

For instance, similar to how the paint of a vehicle reflects the sun throughout the day. The overall result of a diffuse reflective STOP sign was an increase in nighttime visibility of between 50 and 100 feet.

The drawback of this design strategy was that it was inherently expensive and labor-intensive to construct. It was difficult to save manufacturing time and costs.

Late In The 1930s

A ground-breaking retroreflective sheeting material developed by material scientists at 3M has permanently altered the STOP sign. 

The retroreflective surface functioned by “taking in” a source of light and reflecting a part of it straight back, in contrast to the diffuse reflective beads.

Even though it was groundbreaking, the 3M design wasn’t all that different from the glass bead method. The same glass beads were employed in them as in earlier designs. 

The choice to crush the glass beads to a size somewhat bigger than sand, however, marked the main distinction. After that, the resin was utilized to seal the smashed glass material to the STOP sign’s full face.

This design strategy was successful for a while. Yes, compared to the glass bead method, it did improve the STOP sign’s visibility. 

Yes, it was also (somewhat) less expensive to make. The STOP signs, however, soon accumulated dust, filth, and debris due to their rough surface. 

STOP signs eventually started to seem dingy and drab, which somewhat decreased their visibility. 

The STOP sign’s surface would also get slippery with moisture during bad weather, making it difficult to read.

The STOP sign was covered with a clear, slick coating, which cured the problem after a few years. 

The STOP sign was able to preserve all of its retroreflective qualities because of the transparency of this solution, and the smooth surface prevented dirt and moisture from gathering.

This kind of sheeting is referred to in the industry as “flat-top sheeting,” also called “engineering grade sheeting.”

 It gives drivers an improved seeing distance of up to 500 feet. In areas with less traffic and slower speeds, engineering-grade sheeting is still produced.

Watching Red

Recap: From 1940 to 1950, all new STOP signs made for American usage had the following characteristics:

  • An octagonal form
  • Background color: yellow
  • “Stop” text in black
  • (Slightly inserted from the boundary) Black border
  • (Retroreflective substance (viewable up to 500 ft.)

The Production Was The Problem

Yellow holds up well in situations with plenty of traffic, rocks, sleet, sunshine, exhaust, and rain. Red, on the other hand, deteriorated too rapidly, necessitating sign replacement (which adds to cost, time, etc.).

Early red STOP signs serve as a reminder of this problem. The producers still weren’t quite sure how to paint the sign in a red that would withstand fading and slow, but steady deterioration, even after advice from the Manual of Uniform Traffic Control Devices.

Therefore, it would take a few more years before STOP sign producers were able to perfect the “formula” for the required red hue. Take into account the following to help you maintain perspective in all of this.

Nearly ten years before many of the current government agencies and organizations focused on traffic management were fully constituted, these design iterations were taking place. 

For instance, it wasn’t until 1970 that the National Highway Traffic Safety Administration (NHTSA) was established as a byproduct of the Highway Safety Act. 

Engineers, scientists, and drivers were aware of the necessity to increase road safety even at this late date in history.

Future STOP Sign Design Considerations

Today’s STOP sign design presents new difficulties. Retting, Weinstein, and Solomon (2003) estimate that there are around 700,000 motor vehicle collisions involving police reports each year at STOP signs. 

Additionally, around a third of these complaints featured one or more injured drivers or passengers (Retting et al., 2003).

New STOP sign design ideas are already being produced in high-risk regions to meet these issues (e.g., school zones, and heavy pedestrian traffic). 

For instance, junctions with a high risk of driver attention are starting to use STOP signs with LEDs around the perimeter of the sign. 

These kinds of STOP signs stand out more amid the flashing lights from ads and the continual battery of headlights and taillights, making them ideal for places with bustling downtowns, increasing nighttime activities, and high pedestrian traffic.

However, the cost of manufacture rises as more technology is put into the STOP sign design. 

In fact, the production of each of these high-visibility LED STOP signs costs about $450. As a comparison, consider the cost of a normal STOP sign, which is often less than $100.

Beyond technology considerations, there are other conundrums that human factors engineers, sociologists, and traffic scientists need to better comprehend. 

Consider the issue of the number of drivers rushing through your area as an illustration of these problems. 

They put a lot of work into gathering signatures for a petition and getting a few STOP signs put up at important crossroads to reduce traffic.

Right, The Issue Is Resolved

Okay, no. In fact, the complete opposite. Numerous studies conducted by the Institute of Transportation Drivers are likely to “compensate” by speeding even when speed bumps and other traffic calming devices actually reduce vehicle speed as it approaches the speed hump (Johnson & Nedzesky, 2004).

“Compensate” by speeding has shown that placing too many STOP signs in a residential area might encourage speeding. 

The rationale? When drivers come to a complete stop, they try to make up for “lost time” by driving quickly through stop signs. especially when drivers are used to the route.

Detour: You may want to reconsider your position if you believe strategically placed speed bumps would be more effective than STOP signs. 

While speed bumps and other traffic calming measures do result in decreased vehicle speed while entering the speed hump (Johnson & Nedzesky, 2004), it is probable that drivers will “compensate” by speeding up significantly upon leaving the speed hump.

This is one of several STOP sign design conundrums that will need to be solved in the future. 

Human factors engineers may contribute to issues like enhancing safety, awareness, and compliance. 

Prior to generating knowledgeable, wise design suggestions, it will be tough to understand how and why drivers perceive and react to STOP signs in a variety of settings, driving situations, and social surroundings.

  • February 8, 2023