At a flashing yellow light, you are legally required to slow down and proceed with caution. You do not need to stop. This is the key difference between a flashing yellow and a flashing red, which functions like a stop sign. A flashing yellow simply means the intersection or road ahead needs your extra attention, and you should be prepared to yield to other traffic or pedestrians.
The Circular Flashing Yellow Light
The most common version is a standard round (circular) yellow light that blinks on and off. You’ll typically see these on major streets at intersections where the cross street has a flashing red light. Drivers on the flashing yellow side have the right of way but are expected to reduce speed and watch for vehicles entering from the cross street. Drivers on the flashing red side must come to a complete stop before proceeding.
You may also see flashing yellow beacons attached to warning signs, such as curve warnings, school zone signs, or speed limit signs. These serve as attention-getters. They don’t change your legal obligations beyond what the sign itself says, but they signal that the hazard ahead is significant enough to warrant the extra visual alert. Federal standards require these beacons to flash between 50 and 60 times per minute, a rate designed to be noticeable without being disorienting.
The Flashing Yellow Arrow
A flashing yellow arrow is a newer, more specific signal used at left-turn lanes. It means you may turn left, but only after yielding to all oncoming traffic and any pedestrians in the crosswalk. Oncoming traffic has a green light during this phase, so you need to find a safe gap before turning. Think of it as the left-turn equivalent of “proceed with caution.”
This is different from a solid green arrow, which gives you a protected turn with no oncoming traffic to worry about. It’s also different from a solid red arrow, which means you cannot turn at all and must wait. The flashing yellow arrow sits in between: you have permission to turn, but the responsibility to judge when it’s safe falls entirely on you.
Research from the National Cooperative Highway Research Program found that flashing yellow arrows are actually safer than the older method of using a standard green circle to indicate an unprotected left turn. A study led by David Noyce at the University of Wisconsin-Madison concluded that the flashing yellow arrow does a better job of communicating to drivers that they need to yield before turning. Intersections that switched to this signal saw measurable reductions in left-turn crashes.
Flashing Yellow vs. Flashing Red
The distinction matters because the two signals require completely different actions:
- Flashing yellow: Slow down and proceed with caution. No stop required. You have the right of way over cross traffic that faces a flashing red.
- Flashing red: Come to a complete stop, just as you would at a stop sign. Check for traffic in all directions and proceed only when safe.
At an intersection where one street has flashing yellow and the other has flashing red, the flashing yellow side is treated as the major road. Traffic on that side flows more freely, while traffic on the flashing red side must stop and wait for a gap. If all approaches have flashing red, the intersection operates as an all-way stop.
What “Proceed With Caution” Actually Means
Traffic law doesn’t specify an exact speed reduction for flashing yellow lights. There’s no rule saying you need to drop 10 mph. “Proceed with caution” is a legal standard that means you should be alert, scan the intersection for hazards, and be ready to stop if needed. In practice, that usually means easing off the gas, covering your brake, and checking for vehicles that might enter from side streets or pedestrians stepping into the crosswalk.
You’re most likely to encounter flashing yellow signals late at night, when traffic volumes are too low to justify running full signal cycles. An intersection that uses standard red-yellow-green signals during the day may switch to flashing mode overnight. The major street gets flashing yellow, the minor street gets flashing red. This keeps traffic flowing without forcing drivers to sit at a red light with no one around, while still maintaining right-of-way rules at the intersection.
You’ll also see them during signal malfunctions or power outages, when an intersection can’t run its normal cycle. In these cases, treat the flashing yellow the same way: slow down, scan, and proceed carefully.