Understanding the Flashing Yellow Arrow

Flashing left arrow
A solid red arrow =   STOP. Drivers turning left must stop.
A solid green arrow  =   TURN LEFT. Oncoming traffic must stop. Do not go straight.
   A flashing yellow arrow  =   TURNS ARE PERMITTED WHEN SAFE. You must yield to oncoming traffic and pedestrians and then proceed with caution.
A solid yellow arrow  =   Stop if it is safe to do so.

Light intervals are set short for this illustration only. Actual light intervals vary from signal to signal, depending on traffic and the time of day. 

The Federal Highway Administration is now allowing departments of transportation to use flashing yellow left-turn signals as an option on certain roadway intersections. Currently in Littleton, the traffic department has installed a flashing yellow arrow signal at only one intersection: County Line and Erickson, near the Hampton Inn hotel. The department is considering other locations and will add them as appropriate. The Federal Highway Administration has approved the use of flashing yellow arrows in the latest version of the Manual on Uniform Traffic Control Devices.

How does a flashing left-turn arrow work?
A flashing yellow arrow means left turns are permitted, but you must first yield to oncoming traffic and pedestrians and then proceed with caution. The flashing yellow arrow does not replace the solid yellow arrow and it’s meaning. However, it does replace the green "ball" indication as a signal for a yielding left turn. Drivers should always remember: a flashing yellow = turn with caution.

How should drivers approach a flashing yellow left-turn signal?
Drivers should stop at the intersection, and yield to oncoming traffic. If and when it is safe, make your left turn and proceed through the intersection. When the available time for the flashing yellow arrow ends, the solid yellow left-turn arrow begins. The solid yellow retains its standard meaning: the left turn signal is about to go to red and they should prepare to stop, or prepare to complete their left turn if they are in the intersection.

Why not use a solid green light instead of the flashing yellow arrow?
The solid green light is often misunderstood as a left turn indicator. This is because drivers naturally think "green means go." Traffic making a left turn on a solid green light sometimes does not yield to oncoming traffic, which can result in more crashes. The flashing yellow arrow allows left turns but at the same time communicates the "caution" message to drivers. The flashing yellow arrow is especially effective at intersections with high volumes of traffic.

Are other cities in Colorado using this type of signal?
Yes. Boulder and Aurora have installed signals with flashing yellow arrows on certain intersections. CDOT has also installed several flashing yellow arrow signals on Highway 50.

For more information:
Contact Tim Weaver in the City of Littleton Traffic Division at 303-795-3834.