Signal questions are easiest when you read three dimensions in order: color, steady or flashing display, and circular face or arrow. Then apply any other control and the required protection for people or vehicles already in the conflict area.
Build the meaning from three dimensions
A steady circular green is permissive, not absolute priority. Traffic may make movements that another control does not modify, while yielding to pedestrians lawfully using an associated crosswalk and to vehicles already lawfully within the intersection. A steady green arrow is narrower: it releases only the direction indicated by the arrow, still with the stated yielding conditions. The arrow can independently permit that movement; an additional circular green is not required for the arrow's indicated direction.
| Indication | Reading method |
|---|---|
| Steady circular green | Use permitted movements not changed by another control, then check crosswalk and intersection conflicts |
| Steady circular yellow | The related movement is ending or steady red is about to follow; keep applying the terminating-movement rules |
| Steady circular red | Stop at the first existing boundary in the line-crosswalk-intersection hierarchy |
| Flashing circular yellow | Enter cautiously under other controls and required yielding |
| Flashing circular red | Stop at the defined boundary, then use the rules that follow a STOP-sign stop |
| Steady green arrow | Use only its indicated direction and retain the stated yielding duties |
For steady circular red, do not choose a stopping point by distance from the signal pole. Use the physical hierarchy. The marked stop line comes first. If none exists, remain before the near-side crosswalk. If neither feature exists, stop before entering the intersection. This keeps the vehicle outside the first protected boundary that is actually present. The selected federal meaning does not add a State-specific penalty or turn-on-red exception.
Flashing indications form a useful contrast. Flashing yellow permits cautious entry for movements that other controls do not change, while preserving yielding to lawful crosswalk users and vehicles lawfully in the intersection. Flashing red first calls for a stop at the defined point. Movement after that stop follows the rules applicable after a STOP-sign stop. Steady yellow is different from both: it tells you that a related movement is ending or that steady red will immediately follow, while the rules for that terminating movement continue to apply.
The traps
- Reading circular green as unconditional priority. Permitted traffic still yields to lawful crosswalk users and vehicles already lawfully within the intersection.
- Treating steady yellow as the start of a protected phase. It warns that the related movement is ending or that steady red follows immediately.
- Turning flashing yellow into a stop-and-wait command. It permits cautious entry under other controls and the stated yielding duties.
- Treating flashing red like flashing yellow. Flashing red first requires a stop at the defined point, followed by the rules that govern movement after a STOP-sign stop.
Try it
Where does the MUTCD meaning of a steady circular red signal place the initial stop?
- Only after entering the intersection and proceeding beyond any marked stop line, near-side crosswalk, and conflict area
- At any convenient point beyond the crosswalk
- At the stop line; if none, before the near crosswalk; if none, before the intersection
- Always exactly one vehicle length before the signal pole
Under the MUTCD, what movement does a steady GREEN ARROW permit when it is displayed by itself?
- Every movement through the intersection without yielding
- Only a movement opposite the direction shown by the arrow
- No vehicle movement until a circular green is also displayed, even when the arrow independently indicates the permitted movement
- Only the movement shown by the arrow, with the specified yielding conditions