In common MUTCD designations, R identifies regulatory signs, W warning signs, S school signs, D destination or guide signs, I general information signs, M route markers, OM object markers, and EM emergency-management signs. A suffix such as P often identifies a plaque, while letters after a number distinguish related designs.
At a glance
| Prefix | General family | Examples |
|---|---|---|
| R | Regulatory | R1-1 STOP, R2-1 Speed Limit |
| W | Warning | W11-2 Pedestrian, W20-1 Road Work |
| S | School | S1-1 School |
| D | Destination and service guide | D1 destination, D9 service signs |
| I | General information guide | Information and geographic-reference signs |
| M | Route markers and auxiliaries | Interstate, U.S., state and local route markers |
| OM | Object markers | Markers for obstructions and roadway alignment |
| EM | Emergency management | Evacuation and emergency-information signs |
Reading a designation step by step
Start with the letter prefix to identify the family. Next, read the first number as the series or topic group. The number after the hyphen identifies the design within that group. Additional lowercase letters distinguish related versions, and a capital P commonly indicates a plaque used with another sign.
For example, R2-1 is in the regulatory family and R2 speed-regulation series. W11-2 is in the warning family and W11 non-vehicular or roadway-user warning group.
Codes are identifiers, not installation instructions
A designation helps locate the correct sign detail, but it does not determine where, when, or at what size the sign should be installed. Those decisions depend on the MUTCD provisions for the device, roadway conditions, engineering judgment or study where required, and agency standards.
How to search a code
Enter the complete code in the Sign Finder for the narrowest match. If the suffix is unknown, search the beginning of the code or the visible wording. The Sign Library also lets you browse by sign family.
Frequently asked questions
What does R mean in a traffic sign code?
R identifies the regulatory-sign family.
What does W mean in a MUTCD sign code?
W identifies the warning-sign family, including many permanent warnings and temporary traffic-control warnings.
What does P mean at the end of a sign code?
A capital P commonly identifies a supplemental plaque designed for use with another sign.