Dynamic Amplification Factor (DAF) is a key factor used for the design of highway bridges. Considering its importance in the design phase, this paper aims to understand the effect of different vehicle and bridge parameters on a plate girder bridge with simply supported and continuous supports. The analysis of the bridge is done using CSI bridge software. Validation has been done for simply supported plate girder bridge by comparing the DAF using Influence Line Diagram and using the software. Various factors which affect DAF have been discussed which include the vehicle velocity, axle weight of the vehicle and bridge span. It was observed that DAF is dependent on vehicle velocity and bridge span and is not affected by change in axle weight. Further, DAF obtained has been compared with the codal provisions of different countries such as IRC 6 (2017), BSI (2006) and AASHTO (2017).