What You Must Know about Lane-Use Control Signals
Lane-use control signals are special overhead signals placed over a certain lane or lanes. They permit or prohibit drivers to use the lane beneath the signal.
You can distinguish lane-use control signals from other signs and signals by their placement over a certain lane or lanes and by their distinctive shapes and symbols.
Where Will You See Them?
You will most likely see them on highways with reversible lanes. Such lanes are used to improve traffic flow during rush hours. Certain lanes will typically be open for traffic in one direction during morning commute and in the other direction in the afternoon.
You may also see them on highways without reversible lanes, but where there is a need to indicate the open or closed status of one or more lanes. Typical examples are toll-plazas, parking garages, or freeways where a lane is temporarily blocked by a crash, breakdown, construction activities, or similar temporary conditions.
In heavy freeway traffic, officials may also close lanes to make it easier for traffic to merge from a ramp or other freeway.
Meanings of Different Lane-Use Control Signals
The meanings of lane-use control signal indications are regulated in the Manual on Uniform Traffic Control Devices (MUTCD) by the Federal Highway Administration. They are the following:
The Downward Green Arrow
A steady downward green arrow signal means that you can drive in the lane beneath the signal. Traffic from the opposite direction will face a STEADY red X signal over this lane.
The Yellow X
A steady yellow X signal means that you must prepare to vacate the lane beneath the signal. The signal will change to a red X signal farther down the highway. Change lanes as soon it is practical and safe. When you see the steady red X, you must be in another lane.
Washington State also use a flashing red X to encourage lane change.
The Red X
A steady red X signal indication means that you may not use the lane beneath the signal. The lane may be blocked or used by traffic travelling in the opposite direction. Never enter a lane beneath a red X for any reason. You may be hit by an oncoming vehicle.
The Two-Way Left Turn Arrow
A steady white two-way left-turn arrow signal has the same meaning as the two-way left turn lane sign. You must use this lane for a left turn. You cannot use the lane for through travel or passing other vehicles. Be aware that traffic from the opposite direction may approach you in this lane. It is used for left turns from either direction.
The One Way Left Turn Arrow
A steady white one way left-turn arrow signal means that you must use the lane for left turns, but not through travel or passing. Drivers from the opposite direction will not use this lane for left turns; they will face a steady red X signal over this lane.
The Flashing Yellow X
Some states still use a flashing yellow X to indicate two-way left-turn lanes. It is good idea to study your state’s driver manual. If the flashing yellow X is used in your state, you must know what it means. It may be a common snag on your state’s driver examination.
The Yellow Diagonal Downward Arrow
A steady yellow diagonal downward arrow is sometimes used to emphasize the need to change lanes. It is not national standard or officially included in the Manual on Uniform Traffic Control Devices (MUTCD).
Photo credit toll plaza Dulles – MPD01605