What does the term 'hazard cat eyes' refer to on a single carriageway?

The term 'hazard cat eyes' refers to reflective markers placed at intervals along the road. These markers, often made of plastic or glass, enhance visibility, especially at night or in low-light conditions, by reflecting headlights from vehicles. This helps drivers identify the road's layout and any hazards that may be present, improving safety on single carriageways. The use of these reflective markers is particularly important in demarcating lanes, corners, and other critical areas where visibility may be compromised, thereby aiding in preventing accidents. The other options relate to different safety features but do not specifically refer to reflective markers serving this vital purpose.