Vertical Displacements, accelerations and slab twists of the bridge are restricted for traffic safety and passenger comforts in Eurocode, Shinkansen and Korean regulation. However, these limitations are indirect way for the convenience of bridge designer. The traffic safety can be directly estimated from the reduction rates of wheel loads and passenger comforts can be directly evaluated from acclerations of car-bodies. Also, these regulations can be applied within the bridge span lengh of 120m only. From this reason, it is recommended that bridge/train interaction analysis should be performed for special long bridges. In the present study, traffic safety and passenger comforts are estimated directly by bridge/train interaction responses. Also, the consideration of seismic load with simultaneous action of moving train is done for bridge/train/earthquake interaction analysis. From results, a speed limitaion can be defined for securing traffic safety and passenger comforts of a long span suspention bridge.
