The idea for the construction of the autobahn was first conceived in the mid-1920s during the days of the Weimar Republic, but the construction was slow, and most projected sections did not progress much beyond the planning stage due to economic problems and a lack of political support. One project was the private initiative HaFraBa which planned a "car-only road" crossing Germany from Hamburg in the north via central Frankfurt am Main to Basel in Switzerland. Parts of the HaFraBa were completed in the late 1930s and early 1940s, but construction eventually was halted by World War II.