We investigate the travel mode choice behaviour of both resident and cross-border workers in Luxembourg. Two categories of mode choice are considered: sustainable (public transport) and unsustainable (single occupancy car use), which both depend on a large set of spatial and sociodemographic variables. In particular, we determine whether and how the borders of the four countries involved (Luxembourg, Belgium, France, Germany) affect this choice. The results of a classical binary logistic regression model show that significant variables depend on the area of residence and that some border effects are relevant in the context of the studied cross-border areas. Moreover, the identification of these various border-effect variables does not require the use of big data processing techniques. Therefore the proposed method can be applied generally to other cross-border areas with an open border context to highlight the effects of border on functional integration. This study is helpful in terms of developing a better understanding of the determinants involved in the use of sustainable transport modes and in supporting decisionmaking to improve transport planning.