A dedicated roadway section allows vehicles to reduce speed safely before exiting a main thoroughfare. These lanes provide a buffer zone, separating slowing traffic from the consistent flow on the primary roadway, thereby mitigating the risk of rear-end collisions and maintaining overall traffic efficiency. An example is observed when a driver intends to leave a highway; they signal their intention, move into the designated lane, and gradually decrease speed to match the posted exit ramp limit.
The implementation of these lanes significantly enhances road safety and traffic management. By segregating deceleration from through traffic, they prevent sudden braking on the main carriageway, reducing congestion and improving traffic flow. Historically, the absence of these features on early road designs contributed to a higher incidence of accidents at exit points, prompting their widespread adoption and standardization in modern highway engineering.