Geosynthetic reinforced soil-integrated bridge systems (GRS-IBS) are gathering huge importance for their ease of construction, reduced construction time, and cost-effectiveness. These systems employ a type of mechanically stabilized earth (MSE) wall to support single-span and multi-span bridges. A typical GRS-IBS structure comprises of three essential components: (1) Reinforced Soil Foundation(RSF), (2) GRS Abutments, and (3) Integrated Approach. The bridge superstructure is supported directly by GRS abutments, made up of closely spaced layers of geosynthetic reinforcement and compacted granular backfill. In this study, the efficiency of GRS-IBS in terms of lateral displacement of facing and the maximum tension developed in the reinforcement with respect to the depth of the abutment is investigated. Numerical simulations were performed using the finite element program, PLAXIS 2D, under the plane strain condition. A parametric study was then performed to study the behaviour of GRS-IBS under live traffic load considering different values for reinforcement stiffness, reinforcement spacing, and friction angle of backfill soil. The results from numerical analyses showed that stiff reinforcement and backfill with high friction angle contribute towards enhancing the performance of the GRS IBS; however, reinforcement stiffness is found to have insignificant effect on the design components when compared to the effect of vertical reinforcement spacing.