Clause 184.108.40.206 of the Canadian Highway Bridge Design Code (CHBDC) specifies an equation for the calculation of transverse moment intensity (My) in the deck slab cantilever due to truck loading in a slab-on-girder bridge system. Also, it states that the transverse moment intensity shall be assumed 2My for the locations within a distance equal to cantilever length of the transverse free end of the deck slab cantilever. However, CHBDC design values do not consider the effects of barrier length, variable thickness of the barrier wall and shape of the cantilever’s edge stiffening on the response. In addition, the longitudinal moment on the deck slab cantilever due to truck loading is as yet unavailable. Thus, a parametric study was conducted, using the finite element modelling, to investigate the effect of these key parameters in the transverse and longitudinal moments at the region of the transverse free edge of deck slab cantilever. Based on the data generated from this parametric study, imperial equations for the transverse and longitudinal moments at the transverse end of the deck slab cantilever were deduced.