GIS-tools enable modelling accessibility fields at different levels of spatial structures (or traffic networks) and better incorporation of accessibility indicators in the gravity models. In the paper, a two-stage raster-based approach is presented, which was used to model the accessibility fields in Slovenia (Drobne et al., 2008). The results of the accessibility analysis were embedded in the extended gravity model of inter-regional commuting flows of employed persons in Slovenia that makes the gravity model more stable and applicable for policy makers.