ABSTRACT: Planned section of the D1 highway between Košice and Michalovce passes through different natural environments. This fact is especially expressed by variable geological structure and geomorphology of the area. Groundwater vulnerability plays from hydrogeological point of view an important role of environmental impact of construction and activity of the highway. Groundwater is in this area bound on different kinds of rock milieu. The main elements by evaluation of hydrogeological relations in specific conditions seem to be specific geohydraulical parameters of the milieu, which are regularly starting elements by evaluation of groundwater vulnerability. Values of approximate logarithmic parameters: Z - index of transmissivity and Y - index of permeability, respectively, were calculated for present rocks as the first step of evaluation. Strictly hydraulical parameters: T - coefficient of transmissivity and k - coefficients of permeability were also determined by a con version of abovementioned indexes. In the case of evaluation of mentioned environmental impact it is necessary to know also water-bearing value of the area, measure of the present impact of utilization of local road communications on groundwater quality and also prognosis of impact of construction and function of D1 highway with proposal of their monitoring.