<p>To investigate the influence of bridge-mounted auxiliary interference structures on the wind field within the bridge deck driving space under crosswind conditions, this research takes a long-span bridge located along the coast of Fujian Province as a case study. A combined approach of wind tunnel testing and numerical simulation was employed to examine the effects of various interference scenarios on the bridge deck wind environment and the aerodynamic forces acting on vehicles. Numerical simulations were first conducted for the most unfavorable bridge cross-section configuration to analyze the incoming wind speed distribution at different heights above the deck. Based on the equivalent wind speed criterion, the wind field characteristics in key traffic areas of the bridge deck were quantitatively evaluated, and the most adverse scenario was identified. Subsequently, wind tunnel experiments were carried out to further investigate the lane-specific wind fields in the bridge deck traffic space and the corresponding aerodynamic force responses of vehicles under interference conditions. The results can provide theoretical reference for vehicle safety assessment on bridge decks and the optimization of wind barrier designs.</p>