The aim of this paper is to contribute to previous methodological studies of the approach to potential accessibility used in the evaluation of development of the road network. This is done by making a threefold analysis, which combines the overall improvement in the level of accessibility, territorial cohesion, and spatial spillovers. Moreover, we use different spatial dimensions (namely national and international) and different distance decay parameters to estimate both the short trips (e.g. commuting) and the long trips (e.g. business trips or tourism). The results are presented at a very detailed spatial scale (i.e. municipalities – LAU-2 units). The paper provides empirical evidence of improvement in accessibility, changes in the degree of territorial cohesion, and spatial spillovers resulting from the recent completion of two sections of motorway in Poland. The selected case studies differ according to their location (i.e. national and European, peripheral vs. central location), population density, and the settlement structure around the investment. The validity of the proposed multidimensional approach to the evaluation of road investments is verified as the combination of different accessibility dimensions and leads to results which differ respecting efficiency, equity and spillover effects. This paper provides arguments to strengthen the need for the tailor-made parameters of potential accessibility indicator and spatial dimension of analysis. They should be adjusted to the main aim of the particular evaluation.