Upper Explorerland Regional Planning Commission
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New flashing yellow arrows to direct left-turning traffic

Do you stay or do you go? Is oncoming traffic stopped? Motorists attempting to make a left turn will no longer have to wonder what message the traffic signal is conveying.

The Federal Highway Administration has adopted the flashing yellow arrow as a national standard for permissive left-turn operations. Several such signals have already been installed in Iowa.

Others will be installed by the Iowa Department of Transportation and local jurisdictions throughout Iowa as agencies upgrade their traffic signals or make improvements at intersections.

The new left-turn signal head has four signals (listed from top to bottom).
1)    Steady red arrow:  Drivers turning left must stop and wait.

2)    Steady yellow arrow:  The left-turn signal is about to turn red. Do not enter the
       intersection if you can stop safely. Complete your left turn if you are already within
       the intersection.
3)    Flashing yellow arrow:  Yield to oncoming traffic and pedestrians; then turn left
       proceeding with caution. Oncoming traffic has a green light.

4)    Steady green arrow:  Drivers can proceed with the left turn. Oncoming traffic
       must stop. Do not go straight.

The flashing yellow left-turn arrow is intended to:

  • Help prevent crashes. A national study demonstrated that drivers found flashing yellow left-turn arrows more understandable than traditional yield-on-green indications.
  • Reduce traffic delays. 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. This helps reduce delays at intersections, which save time and fuel.
  • Provide more traffic management flexibility. The new traffic signals provide traffic engineers with more options to handle variable traffic volumes.

Visit the Iowa DOT’s website at http://www.iowadot.gov/mvd/ods/flashingyellowarrow.html to take a look at the new signals and learn more about their use.