Transport infrastructure improvements are frequently dealt without adequate consideration of land use management issues. Theoretically this would not appear to be consistent with urban economic theory which prioritises the critical role that transportation plays in all urban economic spatial land use patterns. This linkage between transport and land use is clear in evolution of theory from central place theory through to concentric theory and to modern thinking in economic development based on agglomeration and synergy effects. Additional complexities arise in cases where such investments are across administrative borders/jurisdictions or national borders which necessitate detailed research. It is recognised that major implementation difficulties must be addressed to achieve cross border infrastructure development. These arise initially in terms of funding and later in terms of working within differing planning, procedural and local government systems. These projects have been assisted by EU funding of interregional cross border infrastructure projects. In addition, it is increasingly clear that international and EU environmental legislation and Directives means that interregional management and planning systems need to be better aligned. In this paper we examine policy evolution and recent policy outcomes and trends in the Belfast-Dublin corridor in light of the major infrastructure investment which occurred based upon official data within the time period mid 1990s (when many investments commenced) to 2012 (completion and use of those investments). It will investigate recent trends in terms of emerging economic development patterns since the creation of the M1 motorway and improved rail links. The research will incorporate spatial analytic modelling of current and future development trends along the corridor. Specific indicators included in the paper will include population changes in selected centres and appraisal of economic / industrial activities at selected key locations along the corridor. In particular the research will analyse evidence of such development trends and the degree to which they conform or not with stated planning policies. Such policies include local, regional national planning strategies and EU policies as applied in both North and South jurisdictions. While this research is specifically concerned with the transport land-use interface it is clear that related policy issues arise in relation to other cross-border development initiatives in areas such as energy infrastructure in Ireland, the EU and internationally.