R2-1 is the standard regulatory Speed Limit sign. Related R2 signs and plaques address minimum speed, vehicle classes, time conditions, higher-fines zones, and the end of certain limits. School-speed assemblies use school-sign provisions, while advisory-speed plaques used with warnings are not the same as a regulatory speed limit.
At a glance
| Speed message | Common family | Function |
|---|---|---|
| Maximum speed limit | R2-1 | Displays the applicable regulatory maximum |
| Minimum speed | R2 series | Displays a regulatory minimum where established |
| Vehicle-specific speed | R2 plaque or related sign | Qualifies a speed for a vehicle class |
| School speed | S4/S5 assembly | Displays a school-speed condition and its limits |
| Advisory speed | W13 plaque with warning | Advises a safe approach speed for a condition; not the standard R2-1 regulatory limit |
Regulatory and advisory speeds are different
A regulatory speed-limit sign communicates a legally established limit. An advisory-speed plaque accompanies a warning condition and communicates a recommended speed for that condition. Their shapes, colors, designations, and legal functions differ.
Read every qualifier
Times, vehicle classes, “when flashing,” zone boundaries, and other plaques can change when or to whom a speed message applies. Do not identify a sign from the number alone.
Find the correct speed sign
Search “speed limit,” “minimum speed,” “truck speed,” “school speed,” or “advisory speed” in the Sign Finder. Confirm the designation and the authority establishing the speed before specifying a legend.
Frequently asked questions
What is the MUTCD code for a standard Speed Limit sign?
R2-1 is the standard Speed Limit designation.
Is an advisory speed plaque a speed limit?
No. An advisory-speed plaque used with a warning is functionally different from an R2-1 regulatory speed limit.
Who chooses the number on a speed-limit sign?
The displayed limit comes from the applicable legal and engineering process, not from the sign catalog itself.