Reversible lanes are also commonly found in tunnels and on bridges, and on the surrounding roadways — even where the lanes aren't regularly reversed to handle normal changes in traffic flow. The presence of lane controls allows authorities to close or reverse lanes when unusual circumstances (such as construction or a traffic mishap) require use of fewer or more lanes to maintain orderly flow of traffic.
Signals and markings
In the United States and Canada, reversible lane markings are typically a dashed or broken double yellow line on both sides. Most often done on three-lane roads, the reversible lane is typically used for traffic in one direction at morning rush hour, the opposite direction in the afternoon or evening, and as a turning lane at most other times. There is also a transition period (typically 30–60 min) between reversals during which traffic is prohibited to prevent collisions.
Sometimes, lane control signal are placed over the roadway at regular intervals (within sight of each other) indicating which lanes are allocated to which travel direction; a red X indicates the... Read More