Environmental protection issues shaped the plans for a twin-tube vehicular tunnel, 1.45 miles long, outside the village of Steinhaus in Upper Austria. A cut-and-cover operation requiring the excavation of 650,000 cubic yards of soil, the tunnel itself called for 130,000 cubic yards of concrete to be placed. Because the tunnel stands in groundwater, it was built as what the Austrians call a white tank, a water-impermeable concrete body with no added impervious external skin. Demanding Austrian standards for these impermeable concrete structures include a high degree of crack limitation and control of concrete temperatures; the mix temperature must be below 65° F at placement and cannot rise above 105° F during setting.