The U.S. Transportation Department breaks traffic signs into 13 categories according to their function, reports Safety Signs Minnesota. They fall within three major groups that include regulatory signs, warning signs, or guide signs that give notice of traffic laws, warn drivers of upcoming situations and point out areas of interest.
One common safety sign is a warning sign, which typically appears with a yellow background and black image or text, according to Safety Signs MN. It is diamond-shaped. The sign warns drivers of an upcoming stop sign or traffic signal, while in rural areas with a large wildlife population, the sign may contain an image of a deer. It can also precede railroad crossings.
A regulatory sign, which is rectangular with a white background and black text, is placed anywhere and establishes the rules of the road, states Safety Signs MN. The most common type is a speed limit sign. A guide sign is green and square with white text, informing drivers which kind of street they are approaching, such as highways and bike routes. When construction is occurring, an orange diamond-shaped construction sign is put up to let drivers know about road crews and traffic obstructions.
Other types of safety signs include toll road signs, general information signs, emergency management signs and changeable message signs, says Safety Signs MN.