A key aspect of providing the structural safety of road infrastructure, such as viaducts, is seismic retrofitting and the taking up of horizontal actions prompted by aerodynamic and dynamic forces. This paper will focus on the retrofitting of a viaduct by introducing an innovative solution to reprise the shear action induced mainly by wind and earthquake on the existing supporting devices. Before any retrofitting intervention on specific elements of the structure under consideration, the conservative state and the knowledge level were to be defined. This analysis, which is covered in the first part of the paper, focuses on prior interventions, evaluations, and analyses. Subsequently, a later solution is suggested to lessen the viaduct’s vulnerability to transverse actions. In this method, the existing supports continue working until the acting forces reach a certain threshold, surpassing their capacity. At that point, the transverse forces generated by wind and earthquake—which turned out to be dimensional—are absorbed by steel seismic arrestors that are set up at the supports and connected to the underneath bearing pedestals by means of anchorage systems and shear keys. By redistributing the transverse forces, this system enables a significant improvement in the viaduct’s seismic resistance capacity without necessarily having for replacement of the supporting devices and provides adequate bearing capacity against aerodynamic action. The effectiveness of this system has been assessed through numerical analyses on FE models. This study presents an innovative approach to enhance the structural safety of current viaducts against transverse actions like wind and earthquake. Its primary advantage lies in avoiding the need to change supports, thereby preventing disruptions in traffic flow. This represents a significant contribution to civil engineering research in the field of road infrastructure design and retrofitting.