DescriptionDeflection limits are used in today’s highway bridge industry to indirectly limit the amount of vibration induced under normal operating loads. These limits were established based on subjective human responses to out-dated structure types, and have been found to have no correlation to a bridge’s actual vibration behavior or structural longevity. Bridge designers wishing to take advantage of High Performance Steel (HPS) materials are often unnecessarily forced to use heavier girder sections to meet these criteria. This thesis will study the effects of modifying the mass and stiffness of a HPS bridge’s main elements to ensure that its vibration levels are within tolerable limits, despite being in violation of the proposed deflection criteria. The analysis will use the grillage method based on a dynamic bridge-road-vehicle interaction system to establish peak accelerations for typical HPS bridges. Parameters such as deck thickness and girder moment of inertia will then be adjusted to bring the structure’s vibration to an equivalent level as if the bridge were designed using conventional materials but still meeting deflection limits.