On controlled-access highways, what lane is specifically designated for passing?

On controlled-access highways, the left lane is specifically designated for passing. This is due to the design and flow of traffic on such highways. The left lane allows faster-moving vehicles to overtake those traveling at slower speeds in the right lane.

Using the left lane for passing promotes a smoother traffic flow and helps to reduce congestion. It is important for drivers to return to the right lane after completing a pass to maintain the efficiency of traffic movement.

The right lane is typically for vehicles traveling at or near the speed limit, providing a safe and orderly flow. The middle lane is often used to accommodate various speeds but isn't specifically meant for passing. The emergency lane, or shoulder, is reserved for emergencies and should not be used for regular travel or passing.