Driving Basics: Traffic Lights, Signals, and Signs

Written by Bonnie Gringer

Road signs and signals provide drivers and pedestrians with the instructions they need to stay safe on the road. These signs and signals are, with a few exceptions, federally standardized. The regulations are set forth in the Department of Transportation’s Manual on Uniform Traffic Control Devices and Standard Highway Signs. Traffic signs and signals are required to meet the specifications set forth both federally and by individual states. These specifications include what the sign is made of, its shape, and its color. For example, the color red is used only for prohibition signs and lights, like the stop sign and the yield sign. Yellow indicates a cautionary message of some sort. Green provides directional guidance. The shape of a sign is also important. A circular sign indicates a railroad crossing, whereas diamond-shaped signs indicate a warning. This standardization and frequent use of symbols instead of words ensures instant communication, even for drivers who are color-blind or those who can’t understand the language of the place where they’re driving, which helps keep everyone on the roads safer.

Stop for Red

Two important road signs are the yield sign and the stop sign. A yield sign is white and red and triangular in shape. This sign alerts the driver to prepare to stop and/or let another driver pass. When a driver encounters a yield sign, they should decrease their speed and yield to intersecting or oncoming traffic. The yield sign has a similar meaning as a flashing yellow light: Slow down and proceed with caution. Meanwhile, a stop sign signals the driver to stop. The driver may proceed when the intersection is clear. The driver must stop completely; a rolling stop is not permissible when a stop sign is posted. Stop signs are red with white letters. A stop sign has the same meaning as a flashing red light on a traffic light.

Another important sign to notice when driving is any sign with a red circle with a slash through the picture inside the circle. This means that you cannot do whatever the picture indicates. These types of signs may indicate that no parking, biking, or U-turning is allowed, for example.

Orange is also an important color to look out for: Orange signs indicate construction, meaning that the traffic pattern might change or there might be an unexpected obstacle ahead.

Watch the Lines

Pavement markings provide drivers and pedestrians with information in the same way that road signs do. Their purpose is to regulate traffic. Road markings are either white or yellow. Yellow lines indicate that traffic is flowing in two directions. White lines indicate that traffic is flowing in the same direction. The lines may be broken or solid, which lets drivers know if they may leave their lane or not: If the line is solid, don’t cross it.

Lighting the Way

The traffic light is one of the most common signals on the road. Traffic signals control the flow of traffic through intersections. Even young children are taught what the three colors of the traffic light mean: Red means stop, yellow means caution, and green means go. Although traffic lights are now used for automobile traffic, their initial use came before the car’s invention. They were used in the 1800s to control horse carriage traffic and to help pedestrians avoid being hit when crossing the street. At that time, they were fueled by gas and had to be controlled manually.

In 1912, American police officer Lester Wire envisioned the first electric traffic light. This is the basis for the systems used today, with one distinct difference: Wire’s design had a red light, a green light, and a buzzer that sounded when the signal was about to change. In modern designs, that buzzer was replaced with a yellow light. The invention of computers has also brought innovation to the traffic light. Now, traffic lights can change automatically based on traffic, saving a lot of wait time for drivers.