Some turn lanes have multiple arrows, allowing you to turn left or right, or even to go straight. To discourage drivers from changing lanes near an intersection, turn lanes are separated from through traffic lanes by solid white lines. On some roads, a center turn lane between two opposing directions of traffic is designated for left turns only from either direction. This lane is marked by parallel solid and dashed yellow lines, sometimes accompanied by white arrows painted on the pavement that alternately point left and right. Vehicles moving in either direction can use these lanes to make left turns into another road or driveway.
Reversible lanes are an efficient way to minimize urban traffic during rush-hour periods.
They are separated by dashed double yellow lines. You may cross these lines only if the overhead signal above the lane you wish to enter has a green X or if a sign permits you to do so. Carpool lanes are restricted to vehicles carrying two or more occupants. They are usually on the far left side of a freeway and are separated from other traffic lanes by combinations of white or yellow lines. In some areas pavement messages are used to warn drivers of conditions ahead.