The North Dakota Department of Transportation (ND DOT) has revised a number of traffic signals to the new “flashing yellow arrow” left-turn signals at 15 intersections in Bismarck. The new signals are installed from 3rd Street through Divide Avenue on Bismarck Expressway, and on University Drive from Bismarck Expressway to Airport Road. This is a signal upgrade project. The flashing yellow arrow signals and the programming of the signals is a work in progress. The protected left turn arrows (steady green arrows) at designated intersections are are expected to be fully completed soon.
The signals are designed to improve safety and manage the flow of traffic through the intersections. A flashing yellow arrow means left turns are permitted, but you must first yield to other traffic and pedestrians, and then proceed with caution. The flashing yellow arrow replaces the green ball indicator for a yielding left turn; drivers yield to oncoming traffic. If and when it is safe, drivers then make the left turn and proceed through the intersection. When a flashing yellow arrow ends, the solid yellow arrow begins, meaning the left turn signal is about to change to red and drivers should prepare to stop or prepare to complete their left turn if they are in the intersection.
The changes are being made to comply with federal rules for new traffic signals. Green ball indications are no longer allowed over left-turn lanes. Flashing yellow arrow left-turn signals have been shown to be safer, more efficient, and more flexible than traditional signals.
Why the change?
Safety: A national study showed drivers made fewer mistakes with flashing yellow arrow indications than with the existing green ball indications.
Efficiency: Green left turn arrows can be used either before or after through traffic has a green ball. This improves signal timing progression and traffic flow in signalized corridors.
Flexibility: Left turn signal operations can now change during the day to better respond to fluctuations in traffic volumes. For example, during rush hour if there are few gaps in oncoming traffic, the signals can be more restrictive and only allow left turns on a green arrow. When rush hour is over and there are more gaps in oncoming traffic, the signals can then be less restrictive and allow left turns on green arrows and/or flashing yellow arrows.
For more information and to view a video of the new Flashing Yellow Arrow Left-Turn Signal please view the Flashing Yellow Arrow link below.