The intervention aims at the safety enhancement of the S.S. 658 “Potenza – Melfi” (from Km 0+000 to Km 48+131) within the Lucanian municipalities of Filiano, Avigliano, and Pietragalla. The primary objective is to preserve the existing road shoulders and related furnishing elements, adapting the road alignment only to integrate the new climbing lane. This choice necessitated a substantial modification of the planimetric and altimetric sequence along the three sections. In Section 1, the alignment on the Potenza side is maintained for the extension of the TO01 culvert towards Melfi. Section 2 retains the alignment on the Melfi side to optimize the interventions on the culverts and the ST02 underpass, and includes a 70-degree entry ramp for the San Giorgio junction. Finally, Section 3 is also aligned with the Melfi-bound shoulder, allowing for the near-total remediation of the existing wall and the adjustment of the ST03 underpass to the road gauge only on the Potenza-bound side.