The intervention is aimed at the safety enhancement of most of the S.S. 658 “Potenza – Melfi” (from Km 0+000 to Km 48+131) within the municipalities of Filiano, Avigliano, and Pietragalla. The fundamental design strategy was to preserve one of the two existing road shoulders as much as possible, maintaining its alignment (even though this resulted in a substantial modification of the planimetric and altimetric elements of the sections) and the marginal furnishing elements, especially where the new climbing lane is introduced. Specifically, Section 1 maintains the alignment on the Potenza-bound shoulder to allow for the extension of a culvert (TO01) only in the Melfi direction. Section 2 preserves the alignment on the Melfi-bound shoulder, which optimizes interventions on culverts and underpasses (TO03, TO04, ST02). Furthermore, the entry ramp for the San Giorgio junction in this section was designed with a 70-degree incidence relative to the main road axis. Finally, Section 3, also aligning itself with the Melfi-bound shoulder, enables the remediation of the existing retaining wall for almost its entire length and the adjustment of the underpass (ST03) to the new road gauge exclusively on the Potenza-bound side.