The existing studies of ride comfort are based on wind-vehicle-bridge coupled vibration, which seldom consider the effects of both traffic random characters and road surface progressive deterioration, thus they cannot match very well for the real situation of the bridge under the random traffic loads. Based on wind-traffic-bridge system under random traffic loads, this paper studied the ride comforts taking into account the road surface progressive deterioration. We presented a three-dimensional vehicle model with 24 degrees-of-freedoms (DOFs) including a three-dimensional suspension seat model and longitudinal vibration of the vehicle, and then introduced an improved CA model considering the influence of the next-nearest neighbor vehicle and a progressive deterioration model for road-roughness. The wind-traffic-bridge coupled equations were established by combining the motion equations of both the bridge and vehicles using the displacement relationship and interaction force relationship at the patch contact. The numerical simulations show that the proposed method can rationally simulate the vibration of the wind-traffic-bridge coupled system; and the 3-D vibrations of the driver seat model can significantly affect the drive comforts.