A current design standard provides the deflection limits of structures from the viewpoint of running safety and riding comfort up to 260km/h operation. In this study, the influence of dominant parameters on the dynamic response of vehicles running on structures was examined by numerical analysis to expand the applicability of the design standard in the high-speed range. In addition, the dynamic responses of vehicles on 17 actual structures of various types with different span lengths were measured mainly through vehicle running tests. Carbody acceleration was also measured in relation to structure deflection and studied from the viewpoint of the span length and rigidity of the structures. Peak-to-peak amplitudes of carbody acceleration were approximately 1.5m/s² or less on all structures. A new provision for the railway design standard was proposed based on this study.