A Comparison Of The Dynamic Performance Of A U.S. And A European Heavy Vehicle

Despite the general similarity of U.S. and European heavy trucks, there are differences in design properties that affect braking and turning performance. A European tractor-semitrailer was studied for the purpose of comparing its properties to those of U.S. vehicles and assessing the comparative performance. Mass, suspension, and braking system properties of the European tractor and semitrailer were measured in the laboratory and on the proving ground. Turning and braking performance qualities were evaluated by computer simulation and by experimental tests. In turning performance the European combination had a 9 percent advantage in rollover threshold, compared to a generic U.S. vehicle with properties that were in the midrange of U.S. design practice. Higher suspension roll stiffness and higher chassis weight on the European tractor and semitrailer accounted for the higher threshold. The European combination also had a performance advantage in braking when empty due to the use of load-sensing proportioning valves on the tractor and semitrailer. When loaded, however, braking performance of the U.S. combination was superior to that of its European counterpart