Type D 360-degree warning beacons are used at night to mark which location?

Type D 360-degree warning beacons are specifically designed to enhance visibility and alert drivers to important safety information in low-light conditions. When used at the edge of a roadway, these beacons serve to clearly delineate the boundary of the driving surface, helping to prevent accidents by ensuring that drivers are aware of nearby hazards that may not be easily visible at night. This application is crucial, as vehicles need to maintain proper distances from the edge to avoid going off the road or colliding with static obstacles.

In contrast, the other situations provided would not typically require the use of a Type D 360-degree beacon in the same way. For example, at entry points to construction sites, while safety notifications are essential, other types of signage or lighting might be utilized that are more specific to construction zones. The center of a roundabout and pedestrian crossings also have different safety requirements that include distinct signage and traffic control devices aimed at managing the flow of forward-moving traffic, as well as ensuring pedestrian safety. Thus, using these beacons at the edge of the roadway is the most fitting answer, as it addresses a specific need for visibility and safety at night in that context.