Bridge vibration has become a very important issue since the development of High Performance materials. There is no rational serviceability criterion that can reliably control vibration. Live load deflection, which was introduced in AASHTO Specifications in 1936, was originally set to control undesirable vibration. Prior research shows that the deflection criterion does not necessarily control bridge vibration. Therefore, there is a need to provide a new serviceability criterion that can reliably address bridge vibration issue. Dynamic behavior of a bridge under moving trucks is a complicated problem with a lot of possibilities in loading and bridge vibrational characteristics. In this paper the results of an analytical study that employs 2-D and 3-D Finite Element (FE) models are presented. The purpose is to evaluate the dynamic response of bridges under moving truck load. The effect of vehicle length, vehicle speed, bridge frequency, span length, and load sequence are investigated. The results of this study, unlike almost all prior studies, are presented for all bridge responses, namely displacement, velocity, and acceleration in dimensionless values. Therefore, they can be used for any types of bridges and loads.