Yellow Sign

Road Sign Colors and Shapes

If you read our recent post on the history of road signs, you may recall that the first stop sign appeared in Detroit in 1915 — but it didn’t really look anything like it does today. The New York Times reports that the first stop sign was a 2-foot square metal sheet that had black letters on a white background. The stop sign — and many of the other signs created to help guide motorists and provide important information — evolved over the decades into the recognizable shapes we’re accustomed to today.

The Shape of Things

In 1923, the shapes of signs started to evolve. The New York Times reports that after that first, square stop sign, other signs with more sides were designed to indicate a higher level of danger. A circular sign denoted the most risk, thanks to what can be seen as its infinite number of sides. As a result, circular signs were recommended for railroad crossings. The stop sign adopted an octagonal shape, which signaled the second-highest level of danger. Diamond-shaped signs were designed to provide warnings, while rectangular signs were intended to provide information. Setting standardized shapes for certain signs made sense since lighting wasn’t always ideal at that time. The thought was that it would be easier for drivers to react to known shapes, even if they couldn’t read the signs at night.

The Black-and-White Era

Not unlike the first TV sets, this first crop of road signs didn’t offer much in the way of color. According to the U.S. Department of Transportation, most early signs were white with black letters, and manufacturing limitations meant that no road sign could be bigger than a 2-foot square.

The Dawn of Color

Color is an important part of road signs today; many drivers know what a sign means simply by those factors alone. Some of those sign colors go all the way back to 1924, when officials began discussing which color combinations to use on various types of signs.

One of the color combinations discussed at that point was the stop sign’s now-familiar white lettering on a red background — but those colors weren’t adopted immediately. At the time, a report indicated that it was easier to see a yellow sign than a red sign at night, so when the first manuals standardizing road sign colors were introduced in the late 1920s, the stop signs were yellow.

The New York Times reports that the color red has always signified the need to stop, and while red stop signs were considered early on, producing a durable, red reflective material wasn’t possible until the late 1940s or early 1950s. The nationwide change from yellow to red stop signs didn’t come until a few years later in 1954, when the DOT’s manual called for a red sign with white letters.

Road Signs Today

Now, stop signs have been red for so long that many people don’t remember it any other way. The colors of other types of road signs can also give an indication of their meaning. Here’s a rundown of some of the more common colors and some examples of signs you might see out on the road:

So, now you know a little more about the shapes and colors of signs — from the plain black-and-white square signs of the 1920s to the iconic colors and shapes of today.