What does the Reduced School Speed Limit Ahead sign mean?
The Reduced School Speed Limit Ahead sign (MUTCD S4-5, S4-5a) is a school zone sign under the federal Manual on Uniform Traffic Control Devices, the national standard the states build from. A lower school speed limit begins shortly; start slowing now.
Source: MUTCD 11th Edition, Part 7, Table 7B-1, checked 2026-09-09.
What shape and color is the Reduced School Speed Limit Ahead sign?
| MUTCD code | S4-5, S4-5a |
|---|---|
| Group | School zone signs |
| Shape | Pentagon or rectangle |
| Color | Fluorescent yellow-green background, black legend and border |
What a pentagon, point up means. School zone or school crossing. Shape and color are both unique to this group.
What fluorescent yellow-green means. Pedestrian, bicycle and school warnings. Reserved so those warnings cannot be mistaken for an ordinary hazard.
School zone signs. A pentagon means school and nothing else, so the outline alone answers the question. Fluorescent yellow-green is weaker evidence, because pedestrian and bicycle signs are allowed the same color, and that asymmetry is where the marks go.
What is the Reduced School Speed Limit Ahead sign often mistaken for?
S5-1, the sign that actually imposes the limit. S4-5 is advance warning only.
|  |
|---|---|
| GroupSchool zone signs | GroupSchool zone signs |
| ShapePentagon or rectangle | ShapeVertical rectangle |
| ColorFluorescent yellow-green background, black legend and border | ColorFluorescent yellow-green SCHOOL panel above a white speed limit panel with black legend |
| What it meansA lower school speed limit begins shortly; start slowing now. | What it meansThe lower figure binds only while the beacon is lit, or inside the hours printed on the plaque. |
What are the other school zone signs?
All 7 school zone signs on one page, or every US road sign by shape and color.
Test yourself on this sign and the rest of the set with a road signs practice test for Florida, Texas or California.
The artwork is the federal design itself, which the manual dedicates to the public domain in MUTCD 11th Edition, Part 1, Section 1D.06, checked 2026-09-09. The Interstate Shield, the 511 pictograph and the National Scenic Byway graphic are named exceptions and are not reproduced anywhere on this site.
Source: Manual on Uniform Traffic Control Devices, 11th Edition. Not affiliated with or endorsed by the Federal Highway Administration or any state agency.