11/19/2009
New flashing yellow arrows replace green 'ball' in left-turn signals
MOSCOW - The Idaho Transportation Department has introduced a new flashing yellow arrow, like those being installed nationwide, at an intersection in Moscow.
The newest flashing arrow is planned for a traffic signal at the intersection of U.S. 95 and D Street in the northern part of Moscow. The flashing yellow arrow indicates drivers should proceed left with caution while yielding to oncoming traffic. The new signals are known as flashing yellow arrow left-turn signal, and offer several advantages over the old left-turn signals:
- It's safer - A national study conducted by the Federal Highway Administration demonstrated that drivers made fewer mistakes with the new signals than with traditional left-turn-arrow signals.
- It's more efficient - The new signals provide traffic engineers with more options to handle variable traffic volumes, and save motorists time and fuel.
- It's more consistent - Motorists will see the new signals in every state because the signals are being accepted as a new standard in the Manual on Uniform Traffic Control Devices, which governs highway sign and traffic signal uniformity nationwide.
The signal has four intervals:
- Green arrow - represents a protected turn; drivers have the right of way when turning left
- Flashing yellow - proceed left with caution while yielding to oncoming traffic
- Solid yellow - traffic change coming, prepare to stop
- Solid red - stop
The flashing yellow arrows replace the permissive green ball traditionally used in five-section left-turn traffic signal configurations. Flashing yellow arrows indicate a permissive move for drivers turning left after they yield to oncoming traffic.
If the signal detects that vehicles are not moving through the left-turn lane, a solid green arrow phase will follow, providing protected left-turn movements to clear the intersection. The green ball governing left turns in older five-section signal heads has led some motorists to wrongly think they have a protected turning movement. In contrast, highway users seem to intuitively know the flashing yellow is communicating the need for caution in the turn.
The Federal Highway Administration is making the flashing yellow display the preferred standard for signalized left-turns. It likely will, however, take several years for the display to be implemented by all highway agencies and municipalities in Idaho.