TOPAS (tank truck with optimum and active safety equipment) was a research project of the in the mid-1980s. In view of the increase in the safety of tank trucks that became evident from this research project and of the results obtained from tanker crash tests carried out in conjunction with the DEKRA, Ellinghaus saw the need to apply the knowledge gained to cylindrical pressure tanks as well. The result of this was the enhanced safety tank truck UNITAS 2000. The biggest difficulty in realizing this project was to lower the centre of gravity, in order to achieve not only a high level or stability against overturning, as in the case of TOPAS, but also the excellent road performance of this vehicle type, whereby it had to be born in mind that cylindrical tanks are all tested with an internal pressure of 4 bars. To attain this goal while retaining strength against the bar internal pressure, the forward part of the tank deviated from the ideal cylindrical form and a so-called aerofoil profile was used in this area instead. The special feature of such a profile is that in the upper shell pressure-stresses occur and in the lower shell tensile stresses, while the disastrous bending-stresses are almost completely obviated. The necessary static calculations for type approval were carried out using a finite element program that was hired in America. The usual hoop has been replaced on the UNITAS 2000 by an arrangement that provides the same level of safety with a normal wall thickness of 5,12 mm. The dome fittings were lowered into the outer contour of the tank, thus achieving a vehicle height saving of 400 mm. As a result, the dome fittings are protected in the case of the vehicle overturning in an accident, and a protection cover for the dome fittings is no longer necessary. The trapezoidal profile also had the advantage of making it possible to reduce the normal vehicle length, leading to better manoueuverability. The vehicle has been tested for operational safety by the Vehicle Owner’s Trade Association and is permitted to display the GS sign.