What is the purpose of cat’s eyes (road studs)?

The purpose of cat's eyes, also known as road studs, is primarily to enhance visibility of the road and lane markings, especially in low-light conditions or at night. They are reflective devices that help drivers see the road layout, particularly the edges and the markings that define lanes. This visual guidance is crucial for maintaining safety, as it assists drivers in orienting themselves on the road and following the correct path. Cat's eyes are designed to catch and reflect headlights from vehicles, making them stand out and significantly improving the overall visibility of the roadway.

The other options do not accurately describe the main function of cat's eyes. While they may contribute to a safer driving experience, their primary role is visibility, not providing a smooth surface, indicating speed limits, or marking pedestrian crossings.