What type of device must the Contractor attach to the paver screed if specified?

The type of device that must be attached to the paver screed if specified is one that is capable of constructing a shoulder wedge. This is because the process of paving often involves creating specific geometries in the surface to accommodate various roadway needs, such as transitions from the main roadway to the shoulder. The shoulder wedge helps in achieving the correct slope and drainage, which are essential for the longevity of the roadway and for ensuring safety for vehicles traveling on it.

The option focusing on constructing a shoulder wedge aligns with the typical requirements outlined in roadway construction practices. It serves a vital function in establishing a proper finishing edge for the pavement, enhancing both the structural integrity and the functional performance of the roadway.

Other devices mentioned, such as compaction or safety warning devices, serve different purposes that are not directly related to the specific task of shaping the edge of the asphalt or concrete laid by a paver. Similarly, a road marking device is not designed to interact with the screed or shape the shoulder, thus making it irrelevant in this context.