Minnesota Department of Transportation

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Traffic Engineering


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Flashing yellow arrow traffic signals

A safer, more efficient left-turn signal

Graphic of a traffic signal with a flashing yellow arrow

Flashing yellow arrow traffic signals feature a flashing yellow arrow in addition to the standard red, yellow and green arrows. When illuminated, the flashing yellow arrow allows waiting motorists to make a left-hand turn after yielding to oncoming traffic. Otherwise, the new traffic signals work the same as traditional signals.


Flashing yellow arrow signals have been shown to help drivers make fewer mistakes. They keep motorists safer during heavy traffic and reduce delays when traffic is light. A national study demonstrated that drivers found flashing yellow left-turn arrows more understandable than traditional yield-on-green indications (individual traffic signal lights).

Less delay

There are more opportunities to make a left turn with the flashing yellow left-turn arrow than with the traditional three-arrow, red, yellow and green indications.

More flexibility

The new traffic signals provide traffic engineers with more options to handle variable traffic volumes. A flashing yellow arrow signal has the same meaning it always has: left turns may proceed with caution after yielding to oncoming traffic. In the past, flashing yellow arrows in Minnesota were only used when the entire traffic signal was in flash-mode. Use of the flashing yellow arrow has been shown to have several benefits including minimizing delays and enhancing safety by reducing driver errors.

Where its used

The majority of newly installed MnDOT traffic signals will have the flashing yellow arrow option. The flashing yellow arrow may be used at any intersection at any time but the most typical use will be at intersections and times-of-day that have lower volumes, lower speeds and other favorable conditions. Retrofitting existing signals to include flashing yellow arrows can be costly and will only be done on a limited basis, when necessary.

What the arrows mean

red signal lightSolid red arrow: Drivers intending to turn left must stop and wait. Do not enter an intersection to turn when a solid red arrow is being displayed

solid yellow arrowSolid yellow arrow: The left-turn signal is about to change to red and drivers should prepare to stop or prepare to complete a left turn if they are legally within the intersection and there is no conflicting traffic present.

flashing yellow arrowFlashing yellow arrow: Drivers are allowed to turn left after yielding to all oncoming traffic and to any pedestrians in the crosswalk. Oncoming traffic has a green light. Drivers must wait for a safe gap in oncoming traffic before turning.

green signal lightSolid green arrow: Left turns have the right of way. Oncoming traffic has a red light.



In December 2009, after extensive testing, the Federal Highway Administration authorized use of flashing yellow arrows nationwide. A study conducted by the National Cooperative Highway Research Program determined that drivers had fewer crashes with flashing yellow left-turn arrows than with traditional yield-on-green signal configurations.


Jerry Kotzenmacher