Abstract
The aim of the paper is to determine how fast the HSR connection in conjunction with public transport between Brno and Prague should be in order to be time-competitive with car use. Brno and Prague are the largest agglomerations in Czechia and, according to the Czech government’s plan, the first HSR will be built between them. The competitive speed of high-speed trains is derived from mathematical accessibility models created in GIS. The route planner in Google Maps and control supplementary sources were used as a source of data on the speed of public transport connections and the travel time of cars. The effect of a possible relocation of the main Brno railway station is also considered. The derived optimal competitive speed is slightly higher than the current plans assume.