Polyline annotations play a crucial role in training perception models for autonomous vehicles by enabling precise lane detection. By marking the exact boundaries of lanes on road images, polyline annotations help self-driving systems understand and navigate complex road environments with greater accuracy.

In addition to lane detection, polyline annotations are also valuable for identifying other important road features such as street corners, road edges, and borders. This detailed mapping allows autonomous vehicles to interpret their surroundings more effectively, enhancing both safety and navigation capabilities.