Road Sign Meanings: What are the Rules of the Road?

Have you ever passed a road sign and realized you didn’t understand what the message or symbol was telling you to do? Or have you ever wondered if the color and shape of the road sign have a specific meaning? Or simply curious about the road sign meaning?

Drivers must be able to identify road sign meanings quickly and accurately. Understanding must also take place while traveling at what may be high speeds. For that and other reasons, a universal set of guidelines has been established to help people quickly answer, “what do road signs mean?” while driving.

With so many signs on the road, it’s easy to get confused wondering about road signs and meanings. The problem is compounded when language barriers, color vision deficiencies, and illiteracy are factored into the equation. Unfortunately, one wrong interpretation of road sign meanings can lead to a serious accident or injury.  

To help prevent this, the U.S. Department of Transportation (DOT) has increasingly used symbols rather than words to convey the different safety messages on roadways and highways. Pictograms and symbols are easier to recognize and understand, cross various language barriers, and often close the communication gap. Symbols are quickly becoming the standard for traffic control devices throughout the world.

Understanding the traffic signs and meanings can be as simple as recognizing what the colors, shapes, and symbols on the sign represent. For many drivers, this system eliminates the need to read road signs and allows for quick identification of the intended meaning.

For instance, the colors that make up all road signs are an essential indicator of the information they contain. The standards for the design and application of the signs as controlled under the Manual on Uniform Traffic Control Devices (MUTCD) explain the significance of the colors on road traffic signs.

Road Sign Color Meanings

• Red:  Red generally means stop. The use of red on signs is limited to stop, yield, and prohibition signs.
• White: A white background indicates a regulatory sign.
• Yellow: Yellow conveys a general caution message.
• Green: Green shows permitted traffic movements or directional guidance.
• Fluorescent yellow/green: Indicates pedestrian crossings and school zones.
• Orange: Orange is used for warning and guidance in roadway work zones.
• Coral: Coral is used for incident management signs.
• Blue: Blue indicates road user services, tourist information, and evacuation routes.
• Brown: Brown is used to showing guidance to sites of public recreation or cultural interest.

Although the colors play a critical factor in providing consistency throughout the roads and highways, each shape of road signs has a specific meaning, as well. The shape of road traffic signs can alert drivers about the message prior to reading the contents. Depending on weather conditions, the only thing you might be able to make out is the shape of the sign. If that’s the case – the shape of the sign is just as critical as the message, if not more.

Road Sign Shape Meanings

Many road sign meanings can also be established through their outlines. For drivers unable to determine a sign’s color, the shape could play a pivotal role in conveying the intent or meaning of road signs.  

• An octagon road sign conveys the need to stop. A stop sign is the only sign that uses this shape. Combined with its red background, the unique shape makes it easily recognizable even at great distances.
• An upside-down triangle road sign always means “yield.”
• Diamond-shaped road signs always warn of possible hazards ahead. These are traffic signs, temporary traffic control signs, and some pedestrian and bicycle signs.
• Pennant-shaped road signs warn drivers of no-passing zones.
• Round-shaped road signs are used for railroad signs. When you see a round traffic sign, you will likely see a railroad crossing or light rail transit crossing signs ahead.
• A pentagon-shaped road sign provides a warning that a school zone is ahead or a school crossing zone is approaching.
• A square or horizontal rectangle-shaped road sign usually provides guidance to drivers but can be used for a variety of needs. Some common uses for this shape include exit closed, detour, and parking indicator road signs.
• Vertical rectangle road signs are typically used to inform drivers of regulatory notices, such as speed limits.

There are some exceptions to the shape and color rules for road sign meanings. For example, the railroad crossbuck sign is an indicator of an upcoming railroad crossing, but it is not circular. However, the generally uniform application of standards makes it easy to ascertain the meaning of road signs when driving.

The MUTCD has specific requirements for the size of signs and the material the message is printed on, in addition to the color, shape, and symbol as mentioned above. For example, when signs are used at night, they need to be either retroreflective, with a material that has a smooth, sealed outer surface, or illuminated to show similar shape and color both day and night. However, custom traffic signs are often needed for unique messages, too. 

Now that you know the answer to “what do road signs mean?” when it comes to colors and shapes, take a few minutes to read what road sign symbols mean and see a few examples