Red means stop, yellow means the light is about to turn red, and green means go if the intersection is clear. Arrows apply only to the direction they point. A flashing red is a stop sign, a flashing yellow means go with caution, and a dark signal is an all-way stop.
This is the overview. The trickier signals have their own guides linked below.
Solid lights
| Light | Meaning | What to do |
|---|---|---|
| Solid red | Stop | Stop at the line. Right on red after a full stop is allowed unless a sign says no |
| Solid yellow | Red is coming | Stop if you can do it safely; if you're too close, go through carefully |
| Solid green | Go | Go, but yield to anyone still in the intersection; a left turn yields to oncoming traffic |
Arrows
| Arrow | Meaning |
|---|---|
| Green arrow | You may turn that way; oncoming traffic has red (a "protected" turn) |
| Yellow arrow | The protected turn is ending |
| Flashing yellow arrow | You may turn, but yield to oncoming traffic and people |
| Red arrow | Don't turn that way |
The flashing yellow arrow confuses the most drivers: see flashing yellow arrow meaning.
Flashing and dark lights
- Flashing red: stop, then go when safe, like a stop sign. Flashing red light meaning.
- Flashing yellow: slow down and watch for cross traffic; no stop needed.
- Dark (not working): stop, then all-way stop rules. Traffic lights out.
Turning on red
Right on red is legal in every state after a full stop and yielding, unless a NO TURN ON RED sign is posted, and except in New York City. Left on red is allowed in some states from a one-way street onto another one-way street. Can you turn right on red?
Signal AheadMUTCD W3-3
No Turn on RedMUTCD R10-11
Left Turn Yield on GreenMUTCD R10-12
Stop Here on RedMUTCD R10-6Green doesn't mean the way is clear
A green light gives you permission, not protection. Before entering, check left and right for someone running the red, and don't enter if traffic ahead would leave you stuck in the intersection when the light changes. Blocking the box can cost you a ticket, and on a road test it's a fault.
Signal Ahead signs
A yellow diamond with a traffic light on it warns that a signal is ahead that you may not see yet, often after a curve or a hill. Slow down and be ready to stop.
Practice it
Signal Lab puts every one of these lights in front of you, from a solid yellow to a blackout.
Try the traffic lights topic in Signal LabStart ›Every rule with its source: yellow, green arrow, flashing red, flashing yellow, light out.
