Driving safety guide · Ford of Peoria · Peoria, IL
Road Sign Shapes and Colors Explained
You can often tell what a road sign means before you can read it. The federal Manual on Uniform Traffic Control Devices (MUTCD) sets the shapes and colors so drivers can recognize each kind of sign quickly. Here is what they mean.
The short answer
Shape and color tell you the kind of sign. The octagon is reserved for STOP, the downward-pointing triangle for YIELD and the pennant for NO PASSING ZONE; a circle warns of a railroad crossing ahead, and a diamond is a warning. Red means stop or prohibition, yellow means warning, orange means temporary traffic control, green means direction guidance, and blue means road-user services.
Three kinds of road signs
The MUTCD defines signs by their function:
Regulatory signs
Give notice of traffic laws or regulations.
Warning signs
Give notice of a situation that might not be readily apparent.
Guide signs
Show route designations, destinations, directions, distances, services, points of interest, and other geographical, recreational or cultural information.
From the Manual on Uniform Traffic Control Devices (MUTCD), 11th Edition with Revision 1, Section 2A.03, read November 3, 2026. The FHWA's MUTCD home page says the MUTCD defines the standards used by road managers nationwide to install and maintain traffic control devices on all streets, highways, pedestrian and bicycle facilities, and site roadways open to public travel.
What each road sign shape means
The MUTCD says standardized colors and shapes are specified so that the classes of traffic signs can be promptly recognized. Its Table 2A-1 assigns these shapes:
| Shape | Used for |
|---|---|
| Octagon | STOP sign only |
| Equilateral triangle, pointing down | YIELD sign only |
| Circle | Grade Crossing Advance Warning sign only (railroad crossing ahead) |
| Pennant (triangle on its side, pointing right) | NO PASSING ZONE sign only |
| Pentagon, pointing up | School sign and County Route sign |
| Crossbuck (two rectangles in an X) | Grade Crossing sign only |
| Diamond | Warning signs |
| Rectangle, including square | Regulatory, guide and some warning signs |
| Trapezoid | Recreational and cultural interest area guide signs, and the National Forest Route sign |
From the Manual on Uniform Traffic Control Devices (MUTCD), 11th Edition with Revision 1, Sections 2A.04 and 2A.05 (Table 2A-1), read November 3, 2026.
The pennant-shaped sign: NO PASSING ZONE
The pennant is the only sign shaped like an isosceles triangle with its longer axis horizontal and pointing to the right, and it is used only for the NO PASSING ZONE sign. The MUTCD says that, when used, it is installed on the left-hand side of the roadway at the beginning of a no-passing zone identified by pavement markings, DO NOT PASS signs or both.
Our advice: when you see it, do not start a pass.
From the Manual on Uniform Traffic Control Devices (MUTCD), 11th Edition with Revision 1, Sections 2A.05 and 2C.53, read November 3, 2026. The advice in the last sentence is our own.
What each road sign color means
The MUTCD color code gives these general meanings:
| Color | General meaning |
|---|---|
| Red | Stop or prohibition |
| Yellow | Warning |
| Orange | Temporary traffic control |
| Fluorescent yellow-green | Pedestrian, bicycle, playground, school bus and school warning |
| Fluorescent pink | Incident management |
| Green | Indicated movements or actions permitted, and direction guidance |
| Blue | Road-user services guidance, tourist information and evacuation route |
| Brown | Recreational and cultural interest area guidance |
| Black | Regulation |
| White | Regulation |
| Purple | Only for vehicles with registered electronic toll collection (ETC) accounts |
| Coral and light blue | Reserved for future designation |
From the Manual on Uniform Traffic Control Devices (MUTCD), 11th Edition with Revision 1, Section 1D.05, read November 3, 2026. The MUTCD notes these meanings are general; more specific color assignments are given for each class of device.
Yellow and yellow-green warning signs
Unless the MUTCD designates otherwise, all warning signs are diamond-shaped (a square with one diagonal vertical) with a black legend and border on a yellow background. Warning signs larger than the MUTCD's oversized dimensions may be rectangular or square instead, and a non-diamond shape is typical for overhead installations.
Warning signs about pedestrians, bicyclists and playgrounds may use a yellow or a fluorescent yellow-green background. Warning signs about schools and school buses must use fluorescent yellow-green.
The MUTCD also says warning signs must be retroreflective or illuminated, should be kept to a minimum because unnecessary warning signs tend to breed disrespect for all signs, and should be removed or covered when a seasonal or temporary condition does not exist.
From the Manual on Uniform Traffic Control Devices (MUTCD), 11th Edition with Revision 1, Sections 2C.01 and 2C.02, read November 3, 2026.
Orange work zone signs and pink incident signs
Warning signs in temporary traffic control zones, such as work zones, are generally diamond-shaped with a black legend and border on an orange background. One exception is the round Grade Crossing Advance Warning sign, which keeps its yellow background.
Warning signs used for traffic incident management may have a black legend and border on a fluorescent pink background. In emergencies, crews may use yellow warning signs if orange or pink ones are not at hand, and existing yellow signs that still apply may stay in place in a work zone.
From the Manual on Uniform Traffic Control Devices (MUTCD), 11th Edition with Revision 1, Section 6H.01, read November 3, 2026.
STOP, YIELD and other regulatory signs
Regulatory signs are rectangular unless the MUTCD specifically designates another shape, as it does for STOP and YIELD.
A STOP sign is used where a full stop is always required on an approach to an intersection. Where every approach has a STOP sign, an ALL-WAY plaque, with a white legend and border on a red background, is mounted below each STOP sign.
A YIELD sign requires drivers to yield the right-of-way to other traffic. The MUTCD says vehicles controlled by a YIELD sign need to slow down to a speed that is reasonable for the conditions, or stop when necessary, to avoid interfering with conflicting traffic. For more on what to do at crossings and roundabouts, see our railroad crossing safety tips and our guide on how to drive a roundabout.
From the Manual on Uniform Traffic Control Devices (MUTCD), 11th Edition with Revision 1, Sections 2B.02, 2B.04 and 2B.05, read November 3, 2026.
Keep your vehicle ready for the road
The Works® at Ford of Peoria includes a synthetic blend oil change, tire rotation and pressure check, brake inspection, Multi-Point Inspection, fluid top-off, battery test, and a filter, belts and hoses check.
Schedule service online and see our service specials first. Ford of Peoria is at 2211 W. Pioneer Pkwy. in Peoria. Get directions.
Ford of Peoria service hours
| Days | Hours |
|---|---|
| Mon-Fri | 7 a.m.-5:30 p.m. |
| Sat | 8 a.m.-noon |
| Sun | closed |
From Ford of Peoria's website, November 3, 2026. Holiday hours can differ.
Road sign shapes and colors FAQ
What does a pennant-shaped sign mean?
The pennant, an isosceles triangle with its longer axis horizontal and pointing to the right, is used only for the NO PASSING ZONE sign. The MUTCD says that, when used, it is installed on the left-hand side of the roadway at the beginning of a no-passing zone identified by pavement markings, DO NOT PASS signs or both.
What does an octagon sign mean?
The octagon is reserved for the STOP sign. Under the MUTCD, a STOP sign is used where a full stop is always required on an approach to an intersection.
What do orange road signs mean?
Orange means temporary traffic control. The MUTCD says temporary traffic control warning signs, such as those in work zones, are generally diamond-shaped with a black legend and border on an orange background.
What does a yellow sign mean?
Yellow means warning. Unless the MUTCD says otherwise for a particular sign, warning signs are diamond-shaped with a black legend and border on a yellow background.
What does a fluorescent yellow-green sign mean?
It is used for pedestrian, bicycle, playground, school bus and school warnings. The MUTCD requires school and school bus warning signs to use a fluorescent yellow-green background.
What does a pink road sign mean?
Fluorescent pink means incident management. Warning signs used for traffic incidents may have a black legend and border on a fluorescent pink background.
What is a round yellow sign?
The circle is reserved for the Grade Crossing Advance Warning sign, which warns that a railroad crossing is ahead. It stays yellow even in work zones.
What does The Works at Ford of Peoria include?
The Works® at Ford of Peoria includes a synthetic blend oil change, tire rotation and pressure check, brake inspection, Multi-Point Inspection, fluid top-off, battery test, and a filter, belts and hoses check.
Book a routine checkup
Book The Works, which includes a brake inspection, tire rotation and pressure check, and battery test, at Ford of Peoria.
Sources
Sign shapes, colors and uses are from the Federal Highway Administration's Manual on Uniform Traffic Control Devices, 11th Edition with Revision 1 (dated December 2025), read November 3, 2026. This page is a plain-language summary of national sign standards, not legal advice. Service details, address and hours are from Ford of Peoria's own website, checked the same day. Photo is illustrative.
- Manual on Uniform Traffic Control Devices (MUTCD), 11th Edition with Revision 1 (Sections 1D.05, 2A.03, 2A.04, 2A.05, 2B.02, 2B.04, 2B.05, 2C.01, 2C.02, 2C.53, 6H.01), Federal Highway Administration, PDF dated December 2025, read November 3, 2026
- 11th Edition of the MUTCD with Revision 1 (current edition, dated December 2025), Federal Highway Administration, read November 3, 2026
- About the MUTCD, Federal Highway Administration, read November 3, 2026
- General service: The Works, Ford of Peoria, November 3, 2026
- Address and service hours (structured data), Ford of Peoria, November 3, 2026