Reversible lanes are marked with a normal broken double yellow center line on each side of the reversible lane. These dashed yellow lines replace the solid center line you’d normally see separating opposing traffic, signaling that the direction of travel in that lane changes depending on the time of day or traffic conditions. The markings work together with overhead signals and signs to tell drivers whether the lane is currently open to them.
The Double Broken Yellow Line
The key pavement marking that identifies a reversible lane is a pair of broken (dashed) yellow lines running along each edge of the lane. Under federal standards set by the Manual on Uniform Traffic Control Devices (MUTCD), center line markings separating opposite directions of travel are always yellow. Because a reversible lane serves as the center of the road during some periods and a travel lane during others, both bordering lines are dashed rather than solid. A solid yellow line would mean “do not cross,” which would defeat the purpose.
If you see two dashed yellow lines side by side, that’s your visual cue that the lane between them can switch direction. This is different from a single dashed yellow line (which allows passing) and different from a two-way left-turn lane (which uses one solid and one dashed yellow line on each side).
Overhead Lane Control Signals
Pavement markings alone can’t tell you whether a reversible lane is currently heading your way or against you. That job falls to overhead electronic signals mounted above the lane. These signals use three indications:
- Green downward arrow: The lane below is open and you can use it in your direction of travel.
- Steady yellow X: The lane is about to close. You should prepare to move out of it.
- Steady red X: The lane is closed to you. Traffic is flowing in the opposite direction, and you cannot enter it.
These signals function much like a traffic light but for lane access rather than intersection control. The yellow X gives drivers a transition period before the lane flips, similar to how a yellow traffic light warns you before red. You’ll typically see these signals on gantries spanning the roadway so each lane has its own indicator directly overhead.
Reversible Lane Control Signs
Roadside and overhead signs add another layer of information, especially on roads where the lane serves different purposes at different times of day. A reversible lane might carry through traffic in one direction during the morning rush, through traffic in the opposite direction during the evening rush, and function as a two-way left-turn lane during off-peak hours.
Reversible Lane Control signs display which uses are allowed and during which time periods. They use black symbols on a white background: an upward-pointing arrow means the lane is open for through travel, a red X means it’s closed, two opposing left-turn arrows with the word “ONLY” means the lane functions as a two-way left-turn lane, and a single left-turn arrow with “ONLY” restricts it to left turns in one direction. These signs must account for all times of day and days of the week so drivers are never left guessing.
When signs are mounted on posts at the roadside rather than overhead, they’re required to include the words “CENTER LANE” at the top to clarify which lane the instructions apply to. Post-mounted signs can only supplement overhead signs or signals, not replace them.
Transition Zones and Pavement Arrows
Where a reversible lane begins or ends, drivers need guidance shifting into or out of it. Some cities use diagonal arrow markings painted directly on the pavement in these transition zones to steer drivers into the correct lanes. Washington, D.C., uses this approach on Connecticut Avenue, which converts from a balanced two-lanes-each-way layout with street parking to a four-lanes-one-way, two-lanes-the-other-way reversible setup during commute hours. The diagonal arrows on the road surface help drivers understand which lanes are available as the configuration changes.
Intersections along reversible corridors can create confusion, particularly for turning movements. When a reversible lane passes through an intersection, some agencies restrict turns during reversible operation by posting turning lane use signs on the cross streets. A continuous center left-turn lane with dynamic overhead signals is another solution used to handle left turns without creating head-on conflicts.
Movable Barriers on Some Routes
On high-volume roads where a wrong-way entry could be catastrophic, physical barriers replace or supplement painted markings. The most well-known example is the Golden Gate Bridge, which uses a 1.7-mile movable “zipper” barrier system. A specialized machine drives along the roadway and shifts interlocking concrete segments from one side to the other, physically relocating the median to add lanes in the peak direction. This system replaced plastic pylons that had to be moved by hand at the start and end of each rush period and provides a much sturdier separation between opposing traffic.
Zipper barriers are expensive and only practical on corridors with heavy, predictable directional traffic. Most urban reversible lanes rely on the combination of double broken yellow lines, overhead signals, and signs rather than physical barriers.
Why Multiple Markings Are Used Together
Reversible lanes carry an inherent safety risk: a driver who misreads the lane direction is heading straight into oncoming traffic. Studies of reversible corridors have found increases in sideswipe, head-on, and angle collisions, particularly where mid-segment access points like driveways and side streets are frequent. These crashes tend to happen when drivers fail to recognize which lanes are active in which direction.
That’s why no single marking does the job alone. The double broken yellow lines on the pavement establish that the lane can change direction. The overhead signals tell you whether it’s open right now. The signs spell out the schedule and permitted uses. And in the most critical locations, physical barriers remove any possibility of error. If you’re driving on a road with reversible lanes, the overhead signal is the most important thing to watch: green arrow means go, red X means stop.