AbstractThe long-span bridges could frequently experience complex dynamic interactions with wind and traffic, which makes the dynamic response evaluation crucial for ensuring structural and vehicle driving safety. Previous studies have shown that the acceleration/deceleration of vehicles may have a remarkable influence on the bridge dynamic performance, but such influence has seldom been addressed for the long-span bridge under combined actions from the random traffic flow and wind. In the present study, the acceleration/deceleration of the vehicle in random traffic flow is adequately modeled by means of vehicle inertia force (VIF), which is further incorporated into the novel framework of wind–traffic–bridge (WTB) coupled analysis. Subsequently, the established WTB framework is applied to a prototype long-span suspension bridge, in which the influence of VIF on the bridge vertical vibration is investigated comprehensively. The parametric analyses are first conducted to evaluate the influence of VIF on the bridge vertical vibration by varying the key parameters in the WTB system including the traffic density, traffic proportion, gross vehicle weight, road roughness, and wind speed. Furthermore, statistical analyses are also performed to show how the randomness of traffic flow affects the associated dynamic bridge responses. The present study presents a comprehensive perspective on the vertical bridge vibration under wind and traffic considering VIF, which can further serve as a reference for practical design.