In this work a numerical simulation model for computing mechanical responses of a pavement inserted with geogrid at positions- interface of bituminous layer and base course, middle of base course and interface between subgrade and base course was developed by considering viscoelastic nature of bituminous layers. The model is developed in ANSYS software using Finite Element method. Such an analysis plays a vital role in explaining pavement distress and its failure mechanism of a multilayered pavement system. The responses simulated are stress, strain and deformation under dynamic load. Viscoelastic property of bituminous pavement layers and the heterogeneity existed between different pavement layers in terms of material characterization are taken into account for the development of the model. The validation of the model is done by comparing the deflection and stress variation published in articles using ABAQUS software (4 and 6). From the analysis it is found that stress and deformation showed a significant reduction when the viscoelastic property was considered for single and tandem axle configuration; whereas the micro-strain value shows some percentage increment. When the glass fiber geogrid was placed at the middle of WMM layer, a significant reduction of 16.25, 14.9 and 6% on the mechanical responses, deformation, stress and micro-strain respectively is obtained.