The upper level of the arch (the attic) was composed of a series of Corinthian columns and pilasters dividing the space into three rectangular openings. Each of the outer openings was crowned with an Ionic architrave capped with dentils and a projecting geison, in the manner of the lower level. The central opening, however, was flanked by antae with engaged Corinthian half-columns that supported a projecting triangular pediment, which rested above the dentils, geison, and sima that joined to those of the two wings. At the peak of the pediment, there was a small vegetal acroterion. The central opening of the upper level was originally closed off by a thin screen of stone, c. 7 cm thick. Graindor states that the screen of the central opening of the attic was removed for aesthetic reason on the instructions of Queen Amalia, for whom the avenue running past the arch. Hill states that all three openings were closed, but this view has not prevailed.</ref> Only the slots for its mounting are now preserved. The design of this central aediculum-like, niche of the upper level is similar to the architecture of the "scaenae frons" (façade of ancient stage buildings) and highly evocative of the representations of aedicula in wall painting of the 2nd Pompeian style.