What is the primary function of steady burn lights in traffic control?

The primary function of steady burn lights in traffic control is to mark the roadway edge. These lights are typically used in construction zones or areas where visibility might be compromised, such as at night or during inclement weather. By providing a consistent light signal along the edge of the roadway, they help to delineate the boundaries of the safe driving area, ensuring that drivers can clearly see where they should be steering their vehicles. This visual guidance is crucial for maintaining safety as it prevents accidents that could occur due to confusion about the road layout or the presence of workers and equipment nearby.

In specific contexts, other options may serve different functions, but marking the roadway edge is the essential role of steady burn lights, which plays a vital part in traffic control and driver navigation.