A responsible motorist should know the different types of traffic signs. Road signs give a driver various types of information or warnings depending on the shape, color and placement of the sign. According to the Manual on Uniform Traffic Control Devices (MUTCD), a sign must meet five requirements: fulfill a need, command attention, convey a simple meaning, command respect from travelers and give adequate time for proper response.
The octagon is a regulatory sign because it informs motorists to do, or not do, something. This shape is exclusively used for stop signs. The stop sign is reflective to show the same shape and color during both the day and night. Stop signs have a red background with white letters and border.
The diamond is a warning sign; alerting drivers to potentially hazardous road conditions ahead. These warning signs can alert drivers to a sharp curve ahead, caution drivers the road is slippery when wet or alert drivers of a hidden intersection. Warning signs have a yellow background with black letters and border.
The circle is a regulatory sign to inform drivers they should not be doing something. This sign is a red circle outline with a slash through the middle, across a black symbol of the prohibited action. These signs inform drivers not to enter, perform a U-turn or turn left or right.
The pentagon is another type of warning sign, specifically alerting drivers to watch for schoolchildren or pedestrians nearby. These signs are a fluorescent yellow-green for easier visibility in low light and foggy and rainy weather.
The triangle is a different type of regulatory sign that alerts drivers to slow down because another direction of traffic has the right of way. This shape is reserved exclusively for the yield sign. The yield sign has a white background with a wide red border and letters.
The pennant is a warning sign that inform drivers not to pass traffic in front of them. This sign is placed at the beginning of, and at intervals, along a zone where sight distance is restricted or where other conditions make passing traffic dangerous.
There are two different shapes of rectangular signs: vertical and horizontal. Vertical signs are regulatory signs, informing drivers of speed limits, weight limits and railroad crossings. Horizontal signs can be used for a variety of needs. A horizontal sign could inform drivers of a one-way street, a possible road hazard or as a mile marker.